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Sample records for active growing season

  1. Winter climate change affects growing-season soil microbial biomass and activity in northern hardwood forests.

    PubMed

    Durán, Jorge; Morse, Jennifer L; Groffman, Peter M; Campbell, John L; Christenson, Lynn M; Driscoll, Charles T; Fahey, Timothy J; Fisk, Melany C; Mitchell, Myron J; Templer, Pamela H

    2014-11-01

    Understanding the responses of terrestrial ecosystems to global change remains a major challenge of ecological research. We exploited a natural elevation gradient in a northern hardwood forest to determine how reductions in snow accumulation, expected with climate change, directly affect dynamics of soil winter frost, and indirectly soil microbial biomass and activity during the growing season. Soils from lower elevation plots, which accumulated less snow and experienced more soil temperature variability during the winter (and likely more freeze/thaw events), had less extractable inorganic nitrogen (N), lower rates of microbial N production via potential net N mineralization and nitrification, and higher potential microbial respiration during the growing season. Potential nitrate production rates during the growing season were particularly sensitive to changes in winter snow pack accumulation and winter soil temperature variability, especially in spring. Effects of elevation and winter conditions on N transformation rates differed from those on potential microbial respiration, suggesting that N-related processes might respond differently to winter climate change in northern hardwood forests than C-related processes. PMID:24796872

  2. Winter climate change affects growing-season soil microbial biomass and activity in northern hardwood forests.

    PubMed

    Durán, Jorge; Morse, Jennifer L; Groffman, Peter M; Campbell, John L; Christenson, Lynn M; Driscoll, Charles T; Fahey, Timothy J; Fisk, Melany C; Mitchell, Myron J; Templer, Pamela H

    2014-11-01

    Understanding the responses of terrestrial ecosystems to global change remains a major challenge of ecological research. We exploited a natural elevation gradient in a northern hardwood forest to determine how reductions in snow accumulation, expected with climate change, directly affect dynamics of soil winter frost, and indirectly soil microbial biomass and activity during the growing season. Soils from lower elevation plots, which accumulated less snow and experienced more soil temperature variability during the winter (and likely more freeze/thaw events), had less extractable inorganic nitrogen (N), lower rates of microbial N production via potential net N mineralization and nitrification, and higher potential microbial respiration during the growing season. Potential nitrate production rates during the growing season were particularly sensitive to changes in winter snow pack accumulation and winter soil temperature variability, especially in spring. Effects of elevation and winter conditions on N transformation rates differed from those on potential microbial respiration, suggesting that N-related processes might respond differently to winter climate change in northern hardwood forests than C-related processes.

  3. Global-scale pattern of peatland Sphagnum growth driven by photosynthetically active radiation and growing season length

    NASA Astrophysics Data System (ADS)

    Loisel, J.; Gallego-Sala, A. V.; Yu, Z.

    2012-02-01

    High-latitude peatlands contain about one third of the world's soil organic carbon, most of which is derived from partly decomposed Sphagnum (peat moss) plants. We conducted a meta-analysis based on a global dataset of Sphagnum growth measurements collected from published literature to investigate the effects of bioclimatic variables on Sphagnum growth. Analysis of variance and general linear models were used to relate Sphagnum magellanicum and S. fuscum growth rates to photosynthetically active radiation integrated over the growing season (PAR0) and a moisture index. We found that PAR0 was the main predictor of Sphagnum growth for the global dataset, and effective moisture was only correlated with moss growth at continental sites. The strong correlation between Sphagnum growth and PAR0 suggests the existence of a global pattern of growth, with slow rates under cool climate and short growing seasons, highlighting the important role of temperature and growing season length in explaining peatland biomass production. Large-scale patterns of cloudiness during the growing season might also limit moss growth. Although considerable uncertainty remains over the carbon balance of peatlands under a changing climate, our results suggest that increasing PAR0 as a result of global warming and lengthening growing seasons could promote Sphagnum growth. Assuming that production and decomposition have the same sensitivity to temperature, this enhanced growth could lead to greater peat-carbon sequestration, inducing a negative feedback to climate change.

  4. Global-scale pattern of peatland Sphagnum growth driven by photosynthetically active radiation and growing season length

    NASA Astrophysics Data System (ADS)

    Loisel, J.; Gallego-Sala, A. V.; Yu, Z.

    2012-07-01

    High-latitude peatlands contain about one third of the world's soil organic carbon, most of which is derived from partly decomposed Sphagnum (peat moss) plants. We conducted a meta-analysis based on a global data set of Sphagnum growth measurements collected from published literature to investigate the effects of bioclimatic variables on Sphagnum growth. Analysis of variance and general linear models were used to relate Sphagnum magellanicum and S. fuscum growth rates to photosynthetically active radiation integrated over the growing season (PAR0) and a moisture index. We found that PAR0 was the main predictor of Sphagnum growth for the global data set, and effective moisture was only correlated with moss growth at continental sites. The strong correlation between Sphagnum growth and PAR0 suggests the existence of a global pattern of growth, with slow rates under cool climate and short growing seasons, highlighting the important role of growing season length in explaining peatland biomass production. Large-scale patterns of cloudiness during the growing season might also limit moss growth. Although considerable uncertainty remains over the carbon balance of peatlands under a changing climate, our results suggest that increasing PAR0 as a result of global warming and lengthening growing seasons, without major change in cloudiness, could promote Sphagnum growth. Assuming that production and decomposition have the same sensitivity to temperature, this enhanced growth could lead to greater peat-carbon sequestration, inducing a negative feedback to climate change.

  5. Projected changes in Malawi's growing season

    NASA Astrophysics Data System (ADS)

    Vizy, Edward K.; Cook, Kerry H.; Chimphamba, James; McCusker, Brent

    2015-09-01

    Regional climate model projections at 30-km resolution are used to predict future mid-century and late-century growing season changes over Malawi due to global warming under the Representative Concentration Pathway 8.5 business-as-usual emissions forcing scenario. Three different methods for estimating growing season characteristics are applied and evaluated. All three methods yield reasonable growing season length, onset, and demise date estimates over Malawi given the wide range of uncertainty of the observations. The projections indicate the likelihood for a shorter growing season in the future over Malawi south of 13.5°S. At mid-century the growing season length is predicted to be 20-40 % (20-55 days) shorter over the southernmost districts and 5-20 % (5-30 days) shorter over the central districts. By late-century the length is predicted to be 25-55 % (20-70 days) shorter with significant differences extending into northern Malawi. The shorter growing season is primarily associated with an earlier demise date, as no significant change in the onset date is predicted. Analysis of the regional circulation and horizontal moisture flux transport indicates that the earlier demise is associated with an intensification of the thermal low over the Kalahari Desert to the south and west of Malawi and an expansion of the mid-tropospheric Kalahari anticyclone over southern Africa. The stronger thermal low/anticyclone enhances the moisture flux divergence over Malawi suppressing the convective activity at the end of the wet season.

  6. Impact of Faba Bean-Seed Rhizobial Inoculation on Microbial Activity in the Rhizosphere Soil during Growing Season.

    PubMed

    Siczek, Anna; Lipiec, Jerzy

    2016-01-01

    Inoculation of legume seeds with Rhizobium affects soil microbial community and processes, especially in the rhizosphere. This study aimed at assessing the effect of Rhizobium inoculation on microbial activity in the faba bean rhizosphere during the growing season in a field experiment on a Haplic Luvisol derived from loess. Faba bean (Vicia faba L.) seeds were non-inoculated (NI) or inoculated (I) with Rhizobium leguminosarum bv. viciae and sown. The rhizosphere soil was analyzed for the enzymatic activities of dehydrogenases, urease, protease and acid phosphomonoesterase, and functional diversity (catabolic potential) using the Average Well Color Development, Shannon-Weaver, and Richness indices following the community level physiological profiling from Biolog EcoPlate™. The analyses were done on three occasions corresponding to the growth stages of: 5-6 leaf, flowering, and pod formation. The enzymatic activities were higher in I than NI (p < 0.05) throughout the growing season. However, none of the functional diversity indices differed significantly under both treatments, regardless of the growth stage. This work showed that the functional diversity of the microbial communities was a less sensitive tool than enzyme activities in assessment of rhizobial inoculation effects on rhizosphere microbial activity. PMID:27213363

  7. Impact of Faba Bean-Seed Rhizobial Inoculation on Microbial Activity in the Rhizosphere Soil during Growing Season

    PubMed Central

    Siczek, Anna; Lipiec, Jerzy

    2016-01-01

    Inoculation of legume seeds with Rhizobium affects soil microbial community and processes, especially in the rhizosphere. This study aimed at assessing the effect of Rhizobium inoculation on microbial activity in the faba bean rhizosphere during the growing season in a field experiment on a Haplic Luvisol derived from loess. Faba bean (Vicia faba L.) seeds were non-inoculated (NI) or inoculated (I) with Rhizobium leguminosarum bv. viciae and sown. The rhizosphere soil was analyzed for the enzymatic activities of dehydrogenases, urease, protease and acid phosphomonoesterase, and functional diversity (catabolic potential) using the Average Well Color Development, Shannon-Weaver, and Richness indices following the community level physiological profiling from Biolog EcoPlate™. The analyses were done on three occasions corresponding to the growth stages of: 5–6 leaf, flowering, and pod formation. The enzymatic activities were higher in I than NI (p < 0.05) throughout the growing season. However, none of the functional diversity indices differed significantly under both treatments, regardless of the growth stage. This work showed that the functional diversity of the microbial communities was a less sensitive tool than enzyme activities in assessment of rhizobial inoculation effects on rhizosphere microbial activity. PMID:27213363

  8. Climate change in winter versus the growing-season leads to different effects on soil microbial activity in northern hardwood forests

    NASA Astrophysics Data System (ADS)

    Sorensen, P. O.; Templer, P. H.; Finzi, A.

    2014-12-01

    Mean winter air temperatures have risen by approximately 2.5˚ C per decade over the last fifty years in the northeastern U.S., reducing the maximum depth of winter snowpack by approximately 26 cm over this period and the duration of winter snow cover by 3.6 to 4.2 days per decade. Forest soils in this region are projected to experience a greater number of freeze-thaw cycles and lower minimum winter soil temperatures as the depth and duration of winter snow cover declines in the next century. Climate change is likely to result not only in lower soil temperatures during winter, but also higher soil temperatures during the growing-season. We conducted two complementary experiments to determine how colder soils in winter and warmer soils in the growing-season affect microbial activity in hardwood forests at Harvard Forest, MA and Hubbard Brook Experimental Forest, NH. A combination of removing snow via shoveling and buried heating cables were used to induce freeze-thaw events during winter and to warm soils 5˚C above ambient temperatures during the growing-season. Increasing the depth and duration of soil frost via snow-removal resulted in short-term reductions in soil nitrogen (N) production via microbial proteolytic enzyme activity and net N mineralization following snowmelt, prior to tree leaf-out. Declining mass specific rates of carbon (C) and N mineralization associated with five years of snow removal at Hubbard Brook Experimental Forest may be an indication of microbial physiological adaptation to winter climate change. Freeze-thaw cycles during winter reduced microbial extracellular enzyme activity and the temperature sensitivity of microbial C and N mineralization during the growing-season, potentially offsetting nutrient and soil C losses due to soil warming in the growing-season. Our multiple experimental approaches show that winter climate change is likely to contribute to reduced microbial activity in northern hardwood forests.

  9. Elevated CO2 further lengthens growing season under warming conditions.

    PubMed

    Reyes-Fox, Melissa; Steltzer, Heidi; Trlica, M J; McMaster, Gregory S; Andales, Allan A; LeCain, Dan R; Morgan, Jack A

    2014-06-12

    Observations of a longer growing season through earlier plant growth in temperate to polar regions have been thought to be a response to climate warming. However, data from experimental warming studies indicate that many species that initiate leaf growth and flowering earlier also reach seed maturation and senesce earlier, shortening their active and reproductive periods. A conceptual model to explain this apparent contradiction, and an analysis of the effect of elevated CO2--which can delay annual life cycle events--on changing season length, have not been tested. Here we show that experimental warming in a temperate grassland led to a longer growing season through earlier leaf emergence by the first species to leaf, often a grass, and constant or delayed senescence by other species that were the last to senesce, supporting the conceptual model. Elevated CO2 further extended growing, but not reproductive, season length in the warmed grassland by conserving water, which enabled most species to remain active longer. Our results suggest that a longer growing season, especially in years or biomes where water is a limiting factor, is not due to warming alone, but also to higher atmospheric CO2 concentrations that extend the active period of plant annual life cycles.

  10. Climate change, growing season water deficit and vegetation activity along the north-south transect of eastern China from 1982 through 2006

    NASA Astrophysics Data System (ADS)

    Sun, P.; Yu, Z.; Liu, S.; Wei, X.; Wang, J.; Zegre, N.; Liu, N.

    2012-10-01

    Considerable work has been done to examine the relationship between environmental constraints and vegetation activities represented by the remote sensing-based normalized difference vegetation index (NDVI). However, the relationships along either environmental or vegetational gradients are rarely examined. The aim of this paper was to identify the vegetation types that are potentially susceptible to climate change through examining their interactions between vegetation activity and evaporative water deficit. We selected 12 major vegetation types along the north-south transect of eastern China (NSTEC), and tested their time trends in climate change, vegetation activity and water deficit during the period 1982-2006. The result showed significant warming trends accompanied by general precipitation decline in the majority of vegetation types. Despite that the whole transect increased atmospheric evaporative demand (ET0) during the study period, the actual evapotranspiration (ETa) showed divergent trends with ET0 in most vegetation types. Warming and water deficit exert counteracting controls on vegetation activity. Our study found insignificant greening trends in cold temperate coniferous forest (CTCF), temperate deciduous shrub (TDS), and three temperate herbaceous types including the meadow steppe (TMS), grass steppe (TGS) and grassland (TG), where warming exerted more effect on NDVI than offset by water deficit. The increasing growing season water deficit posed a limitation on the vegetation activity of temperate coniferous forest (TCF), mixed forest (TMF) and deciduous broad-leaved forest (TDBF). Differently, the growing season brownings in subtropical or tropical forests of coniferous (STCF), deciduous broad-leaved (SDBF), evergreen broad-leaved (SEBF) and subtropical grasslands (STG) were likely attributed to evaporative energy limitation. The growing season water deficit index (GWDI) has been formulated to assess ecohydrological equilibrium and thus indicating

  11. Growing-season length and climatic variation in Alaska

    SciTech Connect

    Sharratt, B.S.

    1992-03-01

    The growing season has lengthened in the contiguous United States since 1900, coinciding with increasing northern hemispheric air temperatures. Information on growing season trends is needed in arctic regions where projected increases in air temperature are to be more pronounced. The lengths of the growing season at four locations in Alaska were evaluated for characteristic trends between 1917 and 1988. Freeze dates were determined using minimum temperature criteria of O deg and -3 deg C. A shortening of the season was found at Sitka and lengthening of the season at Talkeetna. The growing season shortened at Juneau and Sitka during the period 1940 to 1970, which corresponded with declining northern hemisphere temperature. Change in the growing season length was apparent in the Alaska temperature record, but the regional tendency for shorter or longer season needs further evaluation.

  12. Interactive effects of UV radiation and reduced precipitation on the seasonal leaf phenolic content/composition and the antioxidant activity of naturally growing Arbutus unedo plants.

    PubMed

    Nenadis, Nikolaos; Llorens, Laura; Koufogianni, Agathi; Díaz, Laura; Font, Joan; Gonzalez, Josep Abel; Verdaguer, Dolors

    2015-12-01

    The effects of UV radiation and rainfall reduction on the seasonal leaf phenolic content/composition and antioxidant activity of the Mediterranean shrub Arbutus unedo were studied. Naturally growing plants of A. unedo were submitted to 97% UV-B reduction (UVA), 95% UV-A+UV-B reduction (UV0) or near-ambient UV levels (UVBA) under two precipitation regimes (natural rainfall or 10-30% rainfall reduction). Total phenol, flavonol and flavanol contents, levels of eight phenols and antioxidant activity [DPPH(●) radical scavenging and Cu (II) reducing capacity] were measured in sun-exposed leaves at the end of four consecutive seasons. Results showed a significant seasonal variation in the leaf content of phenols of A. unedo, with the lowest values found in spring and the highest in autumn and/or winter. Leaf ontogenetic development and/or a possible effect of low temperatures in autumn/winter may account for such findings. Regardless of the watering regime and the sampling date, plant exposure to UV-B radiation decreased the total flavanol content of leaves, while it increased the leaf content in quercitrin (the most abundant quercetin derivative identified). By contrast, UV-A radiation increased the leaf content of theogallin, a gallic acid derivative. Other phenolic compounds (two quercetin derivatives, one of them being avicularin, and one kaempferol derivative, juglanin), as well as the antioxidant activity of the leaves, showed different responses to UV radiation depending on the precipitation regime. Surprisingly, reduced rainfall significantly decreased the total amount of quantified quercetin derivatives as well as the DPPH scavenging activity in A. unedo leaves. To conclude, present findings indicate that leaves of A. unedo can be a good source of antioxidants throughout the year, but especially in autumn and winter.

  13. Interactive effects of UV radiation and reduced precipitation on the seasonal leaf phenolic content/composition and the antioxidant activity of naturally growing Arbutus unedo plants.

    PubMed

    Nenadis, Nikolaos; Llorens, Laura; Koufogianni, Agathi; Díaz, Laura; Font, Joan; Gonzalez, Josep Abel; Verdaguer, Dolors

    2015-12-01

    The effects of UV radiation and rainfall reduction on the seasonal leaf phenolic content/composition and antioxidant activity of the Mediterranean shrub Arbutus unedo were studied. Naturally growing plants of A. unedo were submitted to 97% UV-B reduction (UVA), 95% UV-A+UV-B reduction (UV0) or near-ambient UV levels (UVBA) under two precipitation regimes (natural rainfall or 10-30% rainfall reduction). Total phenol, flavonol and flavanol contents, levels of eight phenols and antioxidant activity [DPPH(●) radical scavenging and Cu (II) reducing capacity] were measured in sun-exposed leaves at the end of four consecutive seasons. Results showed a significant seasonal variation in the leaf content of phenols of A. unedo, with the lowest values found in spring and the highest in autumn and/or winter. Leaf ontogenetic development and/or a possible effect of low temperatures in autumn/winter may account for such findings. Regardless of the watering regime and the sampling date, plant exposure to UV-B radiation decreased the total flavanol content of leaves, while it increased the leaf content in quercitrin (the most abundant quercetin derivative identified). By contrast, UV-A radiation increased the leaf content of theogallin, a gallic acid derivative. Other phenolic compounds (two quercetin derivatives, one of them being avicularin, and one kaempferol derivative, juglanin), as well as the antioxidant activity of the leaves, showed different responses to UV radiation depending on the precipitation regime. Surprisingly, reduced rainfall significantly decreased the total amount of quantified quercetin derivatives as well as the DPPH scavenging activity in A. unedo leaves. To conclude, present findings indicate that leaves of A. unedo can be a good source of antioxidants throughout the year, but especially in autumn and winter. PMID:26562808

  14. GrowLab: Activities for Growing Minds.

    ERIC Educational Resources Information Center

    Pranis, Eve; Cohen, Joy

    As students observe plant growth, the questions that naturally arise can provide opportunities for student exploration and discovery. This guide presents a collection of activities for students in grades K-8 that turn students' questions into life sciences learning experiences. The guide contains four chapters, each with background information and…

  15. Photosynthetic Control of Atmospheric Carbonyl Sulfide during the Growing Season

    NASA Technical Reports Server (NTRS)

    Campbell, J. Elliott; Carmichael, Gregory R.; Chai, T.; Mena-Carrasco, M.; Tang, Y.; Blake, D. R.; Blake, N. J.; Vay, Stephanie A.; Collatz, G. James; Baker, I.; Berry, J. A.; Montzka, S. A.; Sweeney, C.; Schnoor, J. L.; Stanier, Charles O.

    2008-01-01

    Climate models incorporate photosynthesis-climate feedbacks, yet we lack robust tools for large-scale assessments of these processes. Recent work suggests that carbonyl sulfide (COS), a trace gas consumed by plants, could provide a valuable constraint on photosynthesis. Here we analyze airborne observations of COS and carbon dioxide concentrations during the growing season over North America with a three-dimensional atmospheric transport model. We successfully modeled the persistent vertical drawdown of atmospheric COS using the quantitative relation between COS and photosynthesis that has been measured in plant chamber experiments. Furthermore, this drawdown is driven by plant uptake rather than other continental and oceanic fluxes in the model. These results provide quantitative evidence that COS gradients in the continental growing season may have broad use as a measurement-based photosynthesis tracer.

  16. 317/319 phytoremediation site monitoring report - 2003 growing season.

    SciTech Connect

    Negri, M. C.; Gopalakrishnan, G.; Hamilton, C.; Energy Systems

    2004-02-20

    In 1999, Argonne National Laboratory-East (ANL-E) designed and installed a series of engineered plantings consisting of a vegetative cover system and approximately 800 hybrid poplars and willows rooting at various predetermined depths. The plants were installed using various methods including Applied Natural Science's TreeWell{reg_sign} system. The goal of the installation was to protect downgradient surface and groundwater by hydraulic control of the contaminated plume by intercepting the contaminated groundwater with the tree roots, removing moisture from the upgradient soil area, reducing water infiltration, preventing soil erosion, degrading and/or transpiring the residual volatile organic compounds (VOCs), and removing tritium from the subsoil and groundwater. This report presents the results of the monitoring activities conducted by Argonne's Energy Systems Division (ES) in the growing season of 2003. ES was tasked with the biomonitoring of the plantation to determine contaminant uptake and groundwater contact. VOCs were found in plant tissue both at the French Drain and the Hydraulic Control locations in varying concentrations, and tritium levels in transpirate was found to continue a trend of higher concentrations compared to the background in the ANL-E area.

  17. [Physical activity among growing children].

    PubMed

    Tammelin, Tuija; Iljukov, Sergei; Parkkari, Jari

    2015-01-01

    Lack of physical activity poses a risk to the health and well-being of growing children, and should also be considered at a medical consultation. According to recommendations, those of 7 to 18 years of age should carry out at least one hour of physical activity daily. Of the Finnish school-aged children, 50% of the elementary school children but only 17% of the secondary school children follow the physical activity recommendations. Some children exercise and play sports in abundance, and in their case it should be especially made sure that the prevention and, when necessary, treatment of exercise-related injuries, overexertion and eating disorders are taken care of.

  18. The hidden season: growing season is 50% longer below than above ground along an arctic elevation gradient.

    PubMed

    Blume-Werry, Gesche; Wilson, Scott D; Kreyling, Juergen; Milbau, Ann

    2016-02-01

    There is compelling evidence from experiments and observations that climate warming prolongs the growing season in arctic regions. Until now, the start, peak, and end of the growing season, which are used to model influences of vegetation on biogeochemical cycles, were commonly quantified using above-ground phenological data. Yet, over 80% of the plant biomass in arctic regions can be below ground, and the timing of root growth affects biogeochemical processes by influencing plant water and nutrient uptake, soil carbon input and microbial activity. We measured timing of above- and below-ground production in three plant communities along an arctic elevation gradient over two growing seasons. Below-ground production peaked later in the season and was more temporally uniform than above-ground production. Most importantly, the growing season continued c. 50% longer below than above ground. Our results strongly suggest that traditional above-ground estimates of phenology in arctic regions, including remotely sensed information, are not as complete a representation of whole-plant production intensity or duration, as studies that include root phenology. We therefore argue for explicit consideration of root phenology in studies of carbon and nutrient cycling, in terrestrial biosphere models, and scenarios of how arctic ecosystems will respond to climate warming.

  19. Increased photosynthesis compensates for shorter growing season in subarctic tundra - seven years of snow accumulation manipulations

    NASA Astrophysics Data System (ADS)

    Bosiö, Julia; Johansson, Margareta; Njuabe, Herbert; Christensen, Torben R.

    2013-04-01

    This study was initiated to analyze the effect of snow cover on photosynthesis and plant growth in subarctic mires underlain by permafrost. Due to their narrow environmental window these raised bogs, often referred to as palsa mires, are highly sensitive to climatic changes. In Fennoscandia palsa mires are currently subjected to climate related thawing and shift in vegetational and hydrological patterns. Yet, we know little of how these subarctic permafrost mires react and feed back to such changes. By using snow fences to hinder snow drift the accumulation of snow was increased in six plots (10x20 m) in a snow manipulation experiment on a subarctic permafrost mire in northern Sweden. The thicker snow pack prolongs the duration of the snow cover in spring, causing a delay in the onset, as well as an overall shortening of the growing season. By measuring incoming and reflected photosynthetic active radiation (PAR) we wanted to address the question whether the increased snow thickness and associated delay of the growing season start affected the absorbed PAR and the accumulated gross primary production (GPP) over the season. The reflected PAR was measured at twelve plots where six of the plots experienced increased snow accumulation (treatment), and remaining six plots were untreated (control). Minikin QT sensors with integrated data loggers logged incoming and reflected PAR hourly throughout the growing seasons of 2011 and 2012. In July - September 2010 PAR measurements were coupled with flux chamber measurements to assess GPP and light use efficiency of the plots. The increased accumulation of snow prolonged the duration of the snow cover in spring, causing a delay in the onset, as well as an overall shortening of the growing season in the treated plots. The end of the growing season was not affected by the snow manipulation. The delay of the growing season start and hence overall shortening of the growing season in the treatment plots was 18 days in 2011 and 3

  20. 317/319 phytoremediation site monitoring report - 2005 growing season.

    SciTech Connect

    Negri, M. C.; Gopalakrishnan, G.; Energy Systems

    2006-03-31

    In 1999, Argonne National Laboratory (ANL) designed and installed a series of engineered plantings consisting of a vegetative cover system and approximately 800 hybrid poplars and willows rooting at various predetermined depths. The plants were installed using various methods including Applied Natural Science's TreeWell{reg_sign} system. The goal of the installation was to protect downgradient surface and groundwater by hydraulic control of the contaminated plume by intercepting the contaminated groundwater with the tree roots, removing moisture from the upgradient soil area, reducing water infiltration, preventing soil erosion, degrading and/or transpiring the residual volatile organic compounds (VOCs), and removing tritium from the subsoil and groundwater. This report presents the results of the monitoring activities conducted by Argonne's Energy Systems Division (ES) in the growing season of 2005. Monitoring of the planted trees began soon after the trees were installed in 1999 and has been conducted every summer since then. As the trees grew and consolidated their growth into the contaminated soil and groundwater, their exposure to the contaminants was progressively shown through tissue sampling. However, as trees grow larger, some of the findings obtained in the early years when trees were much smaller may not hold true now and need to be verified again. During the 2005 sampling campaign, data from the French Drain area confirmed the results obtained in 2004 and earlier, and the previously found correlation between soil and branch concentrations. During the 2005 summer, studies under controlled conditions (cartridges) have shown a generally linear dose response of PCE uptake, and have also shown that tree concentrations of PCE decrease after flushing with clean water in short times when trees are exposed to low levels of the contaminant. This data proves that tree concentrations are transient, and that with proper time levels can return close to background

  1. Growing season surface water loading of fecal indicator organisms within a rural watershed.

    PubMed

    Sinclair, A; Hebb, D; Jamieson, R; Gordon, R; Benedict, K; Fuller, K; Stratton, G W; Madani, A

    2009-03-01

    The loading of microbial contaminants was examined within the Thomas Brook watershed, a 784 ha mixed land-use catchment located in the headwaters of the Cornwallis River drainage basin (Nova Scotia, Canada). The objectives were to: (i) examine spatial and temporal characteristics of fecal bacteria loading during the growing season from five subwatersheds, and (ii) develop areal fecal indicator organism export coefficients for rural landscapes. Fecal coliform, Escherichia coli, total suspended solids (TSS) concentrations and stream flow were monitored at five locations in the watershed over six consecutive growing seasons (May-Oct, 2001-2006). A nested watershed monitoring approach was used to determine bacterial loading from distinct source types (residential vs. agricultural) during both baseflow and stormflow periods. Areal bacterial loading rates increased in each nested watershed moving downstream through the watershed and were highest in the three subcatchments dominated by agricultural activities. Upper watershed bacterial loading throughout the growing season from an agricultural subcatchment (Growing Season Avg 8.92 x 10(10) CFU ha(-1)) was consistently higher than a residential subcatchment (Growing Season Avg 8.43 x 10(9) CFU ha(-1)). As expected, annual average stormflow bacterial loads were higher than baseflow loads, however baseflow loads still comprised between 14 and 35% of the growing season bacterial loads in the five subwatersheds. Fecal bacteria loads were greater during years with higher annual precipitation. A positive linear relationship was observed between E. coli and TSS loading during the 2005 and 2006 growing seasons when both parameters were monitored, indicating that the processes of sediment transport and bacterial transport are linked. It is anticipated that computed areal microbial loading coefficients will be useful in developing watershed management plans. More intensive sampling during stormflow events is recommended for

  2. What makes active regions grow.

    NASA Technical Reports Server (NTRS)

    Weart, S.

    1972-01-01

    A study of magnetic flux growth or growth failure in over 100 active regions is shown to indicate that most growth is connected with the emergence of a large batch of flux in the shape of a new arch filament system (AFS). During the recent sunspot maximum, new AFSs appeared at a rate of nearly one per day over the entire sun. Evidence is presented for two proposed hypotheses, namely: (1) a twist in the flux tubes of new AFSs is a key factor in determining which new AFSs will grow; and (2) this twist is related to the well-known asymmetry of sunspot groups.

  3. Non-growing season nitrous oxide fluxes from agricultural soils

    NASA Astrophysics Data System (ADS)

    Kariyapperuma Athukoralage, Kumudinie

    A two-year field experiment was conducted at the Arkell Research Station, Ontario, Canada to evaluate composting as a mitigation strategy for greenhouse gases (GHGs). The objectives were to quantify and compare non-growing season nitrous oxide (N2O) fluxes from agricultural soils after fall manure application of composted and untreated liquid swine manure. Nitrous oxide fluxes were measured using a micrometeorological method. Compared to untreated liquid swine manure (LSM), composted swine manure (CSM) resulted in 57% reduction of soil N2O emissions during February to April in 2005, but emissions during the same period in 2006 were not affected by treatments. This effect was related to fall and winter weather conditions with the significant reduction occurring in the year when soil freezing was more pronounced. The DNDC (DeNitrification-DeComposition) model was tested against data measured during the non-growing seasons from 2000 to 2004, for farming with conventional management at the Elora Research Station, Ontario, Canada. The objective was to assess the ability of the DNDC model to simulate non-growing season N2O fluxes from soils in southwestern Ontario. Comparison between model-simulated and measured data indicated that background fluxes were relatively well predicted. The spring thaw N2O flux event was correctly timed by the DNDC model, but was smaller than the measured spring thaw event. Though there was no N2O emission event measured in early May, the DNDC model predicted a large event, simultaneous with the physical release of predicted ice-trapped N2O. Removing the large and late predicted emission peak and increasing the contribution of newly produced N2O due to denitrification to the early spring thaw event were proposed. Three data sets from studies conducted in Ontario, Canada were used to estimate and compare the overall GHG (N2O and methane) emissions from LSM and CSM. Compared to LSM storage, the composting process reduced GHG emissions by 35% (CO

  4. Responses of Scots pine to waterlogging during growing season

    NASA Astrophysics Data System (ADS)

    Repo, Tapani; Launiainen, Samuli; Lehto, Tarja; Sutinen, Sirkka; Ruhanen, Hanna; Heiskanen, Juha; Laurén, Ari; Silvennoinen, Raimo; Vapaavuori, Elina; Finér, Leena

    2016-04-01

    For the future management and sustainable use of boreal forests it is crucial to consider the rate and strength of tree responses to an elevated water table and the concurrent oxygen limitations, especially in peatlands. We examined the response dynamics of 7-year-old Scots pine (Pinus sylvestris L.) seedlings to a five-week waterlogging (WL) during a growing season in a root lab experiment. WL took place after shoot elongation had ended whereas growth of the trunk diameter was still in progress. We monitored shoots and roots before, during and after WL treatment. Relations between the shoot and root responses, the latter being the primary target of the WL stress, will be discussed. We hypothesize that root responses, in terms of growth by minirhizotron imaging, will appear with delay as compared with the first symptoms in physiology of above-ground organs.

  5. The seasonal timing of warming that controls onset of the growing season.

    PubMed

    Clark, James S; Melillo, Jerry; Mohan, Jacqueline; Salk, Carl

    2014-04-01

    Forecasting how global warming will affect onset of the growing season is essential for predicting terrestrial productivity, but suffers from conflicting evidence. We show that accurate estimates require ways to connect discrete observations of changing tree status (e.g., pre- vs. post budbreak) with continuous responses to fluctuating temperatures. By coherently synthesizing discrete observations with continuous responses to temperature variation, we accurately quantify how increasing temperature variation accelerates onset of growth. Application to warming experiments at two latitudes demonstrates that maximum responses to warming are concentrated in late winter, weeks ahead of the main budbreak period. Given that warming will not occur uniformly over the year, knowledge of when temperature variation has the most impact can guide prediction. Responses are large and heterogeneous, yet predictable. The approach has immediate application to forecasting effects of warming on growing season length, requiring only information that is readily available from weather stations and generated in climate models.

  6. The seasonal timing of warming that controls onset of the growing season.

    PubMed

    Clark, James S; Melillo, Jerry; Mohan, Jacqueline; Salk, Carl

    2014-04-01

    Forecasting how global warming will affect onset of the growing season is essential for predicting terrestrial productivity, but suffers from conflicting evidence. We show that accurate estimates require ways to connect discrete observations of changing tree status (e.g., pre- vs. post budbreak) with continuous responses to fluctuating temperatures. By coherently synthesizing discrete observations with continuous responses to temperature variation, we accurately quantify how increasing temperature variation accelerates onset of growth. Application to warming experiments at two latitudes demonstrates that maximum responses to warming are concentrated in late winter, weeks ahead of the main budbreak period. Given that warming will not occur uniformly over the year, knowledge of when temperature variation has the most impact can guide prediction. Responses are large and heterogeneous, yet predictable. The approach has immediate application to forecasting effects of warming on growing season length, requiring only information that is readily available from weather stations and generated in climate models. PMID:24115181

  7. 317/319 phytoremediation site monitoring report - 2004 growing season.

    SciTech Connect

    Negri, M. C.; Gopalakrishnan, G.; Bogner, J.; Energy Systems

    2009-02-21

    In 1999, Argonne National Laboratory (ANL) designed and installed a series of engineered plantings consisting of a vegetative cover system and approximately 800 hybrid poplars and willows rooting at various predetermined depths. The plants were installed using various methods including Applied Natural Science's TreeWell{reg_sign} system. The goal of the installation was to protect downgradient surface and groundwater by hydraulic control of the contaminated plume by intercepting the contaminated groundwater with the tree roots, removing moisture from the upgradient soil area, reducing water infiltration, preventing soil erosion, degrading and/or transpiring the residual volatile organic compounds (VOCs), and removing tritium from the subsoil and groundwater. This report presents the results of the monitoring activities conducted by Argonne's Energy Systems Division (ES) in the growing season of 2004. Monitoring of the planted trees began soon after the trees were installed in 1999 and has been conducted every summer since then. As the trees grew and consolidated their growth into the contaminated soil and groundwater, their exposure to the contaminants was progressively shown through tissue sampling. Since the inception of the project, significant progress was made in the refinement and testing of the analytical method (for which no official method is available), the determination of the optimal tissue for sampling, and of the variability of the concentrations within a specific tree. An understanding has also been developed on background concentrations of VOCs, and how to discriminate between VOCs that are associated with plant tissue because of aerial or of soil/groundwater uptake pathways. Also, during the 2003 sampling campaign, core samples from tree trunks were collected for the first time (the trees were large enough to stand the procedure). Data collected from the French Drain area last year supported the hypothesis that a correlation was present between

  8. Plasticity of maritime pine (Pinus pinaster) wood-forming tissues during a growing season.

    PubMed

    Paiva, J A P; Garnier-Géré, P H; Rodrigues, J C; Alves, A; Santos, S; Graça, J; Le Provost, G; Chaumeil, G; Da Silva-Perez, D; Bosc, A; Fevereiro, P; Plomion, C

    2008-01-01

    The seasonal effect is the most significant external source of variation affecting vascular cambial activity and the development of newly divided cells, and hence wood properties. Here, the effect of edapho-climatic conditions on the phenotypic and molecular plasticity of differentiating secondary xylem during a growing season was investigated. Wood-forming tissues of maritime pine (Pinus pinaster) were collected from the beginning to the end of the growing season in 2003. Data from examination of fibre morphology, Fourier-transform infrared spectroscopy (FTIR), analytical pyrolysis, and gas chromatography/mass spectrometry (GC/MS) were combined to characterize the samples. Strong variation was observed in response to changes in edapho-climatic conditions. A genomic approach was used to identify genes differentially expressed during this growing season. Out of 3512 studied genes, 19% showed a significant seasonal effect. These genes were clustered into five distinct groups, the largest two representing genes over-expressed in the early- or late-wood-forming tissues, respectively. The other three clusters were characterized by responses to specific edapho-climatic conditions. This work provides new insights into the plasticity of the molecular machinery involved in wood formation, and reveals candidate genes potentially responsible for the phenotypic differences found between early- and late-wood.

  9. Growing season methane budget of an Inner Mongolian steppe

    NASA Astrophysics Data System (ADS)

    Liu, Chunyan; Holst, Jirko; Yao, Zhisheng; Brüggemann, Nicolas; Butterbach-Bahl, Klaus; Han, Shenghui; Han, Xingguo; Tas, Bart; Susenbeth, Andreas; Zheng, Xunhua

    We present a methane (CH 4) budget for the area of the Baiyinxile Livestock Farm, which comprises approximately 1/3 of the Xilin river catchment in central Inner Mongolia, P.R. China. The budget calculations comprise the contributions of natural sources and sinks as well as sources related to the main land-use in this region (non-nomadic pastoralism) during the growing season (May-September). We identified as important CH 4 sources floodplains (mean 1.55 ± 0.97 mg CH 4-C m -2 h -1) and domestic ruminants, which are mainly sheep in this area. Within the floodplain significant differences between investigated positions were detected, whereby only positions close-by the river or bayous emitted large amounts of CH 4 (mean up to 6.21 ± 1.83 mg CH 4-C m -2 h -1). Further CH 4 sources were sheepfolds (0.08-0.91 mg CH 4-C m -2 h -1) and pasture faeces (1.34 ± 0.22 mg CH 4-C g -1 faeces dry weight), but they did not play a significant role for the CH 4 budget. In contrast, dung heaps were not a net source of CH 4 (0.0 ± 0.2 for an old and 0.0 ± 0.3 μg CH 4-C kg -1 h -1 for a new dung heap). Trace gas measurements along two landscape transects (volcano, hill slope) revealed expectedly a mean CH 4 uptake (volcano: 76.5 ± 4.3; hill: 28.3 ± 5.3 μg CH 4-C m -2 h -1), which is typical for the aerobic soils in this and other steppe ecosystems. The observed fluxes were rarely influenced by topography. The CH 4 emissions from the floodplain and the sheep were not compensated by the CH 4 oxidation of aerobic steppe soils and thus, this managed semi-arid grassland did not serve as a terrestrial sink, but as a source for this globally important greenhouse gas. The source strength amounted to 1.5-3.6 kg CH 4-C ha -1 during the growing season, corresponding to 3.5-8.7 kg C ha -1 yr -1.

  10. Excess growing-season water limits lowland black spruce productivity

    NASA Astrophysics Data System (ADS)

    Dymond, S.; Kolka, R. K.; Bolstad, P. V.; Gill, K.; Curzon, M.; D'Amato, A. W.

    2015-12-01

    The annual growth of many tree species is limited by water availability, with growth increasing as water becomes less scarce. In lowland bogs of northern Minnesota, however, black spruce (Picea mariana) is often exposed to excess water via high water table elevations. These trees grow in thick deposits of organic mucky peat and often have shallow rooting systems to avoid the complete submersion of roots in water. While it is generally believed that black spruce decrease growth rates with rising water table elevations, this hypothesis has not been tested in situ. We used a unique, 50-year record of daily bog water table elevations at the Marcell Experimental Forest (MEF) in northern Minnesota to investigate the relationship between climate and black spruce productivity. Nine 1/20th ha circular plots were established in five different bogs and tree height, diameter-at-breast-height (DBH), and crown class were recorded. Additionally, two perpendicular cores were collected on all trees greater than 10 cm diameter-at-breast-height. Tree cores were sanded, mounted, cross-dated, and de-trended according to standard dendrochronological procedures. Ring width measurements were correlated with precipitation, temperature, and water table elevation using package BootRes in R to determine the climatic variables most associated with stand level productivity. Across the different plots, we found that early growing season water table elevation (May and June) was negatively correlated with both individual and stand-level black spruce growth (p < 0.01), while growth was positively correlated with March temperatures (p < 0.01). No significant relationships existed between black spruce growth and monthly precipitation. If summer water table elevations in these peatland ecosystems rise as is anticipated with more extreme precipitation events due to climate change, we could see an overall decrease in the stand level productivity of black spruce.

  11. Soil microbial biomass alterations during the maize silage growing season relative to tillage method

    SciTech Connect

    Staley, T.E.

    1999-12-01

    Tillage method can significantly alter soil microbial populations and activities. Although considerable literature exists on microbial and soil chemical alterations under various tillage methods, little information exists on soil microbial biomass C (SMB) alterations during the growing season, and especially on the relationship of SMB to crop N use. The objective of this study was to determine the effect of notillage (NT) or conventional tillage (CT), and soil location, on SMB during the growing season. A maize (Zea mays L.) silage/{sup 15}N field experiment, under NT or CT for 3 yr before this study, was used during the fourth growing season. Averaged over sampling times and location (within-row or between-row), SMB in the 0- to 3.8-cm and 3.8- to 7.5-cm soil layers under NT was 87 and 33% greater, respectively, than under CT. Linear regression of soil surface layer (0--3.8 cm) SMB on day-of-year revealed a significant (P {le} 0.10) relationship only within-row and under NT, with a 29% SMB decrease during the growing season. Similar regressions for the other layers and treatments were significant (P > 0.10) or had small seasonal differences. SMB was consistently higher in the between-row locations under both tillage methods. Despite substantial tillage method-induced differences in SMB (50% overall, accompanied by small differential seasonal differences) in the more surficial layers, these alterations appear to have been of little practical consequence, since previous work on these plots revealed essentially no differences in silage utilization of either fertilizer N or soil N relative to tillage method. Thus, the importance of SMB in significantly affecting crop N use in this within-row, banded, maize silage system is questioned.

  12. Impacts of climate change on the growing season in the United States

    USGS Publications Warehouse

    Markstrom, Steven L.; Hay, Lauren E.

    2011-01-01

    Understanding the effects of climate change on the vegetative growing season is key to quantifying future hydrologic water budget conditions. The U.S. Geological Survey modeled changes in future growing season length at 14 basins across 11 states. Simulations for each basin were generated using five general circulation models with three emission scenarios as inputs to the Precipitation-Runoff Modeling System (PRMS). PRMS is a deterministic, distributed-parameter, watershed model developed to simulate the effects of various combinations of precipitation, climate, and land use on watershed response. PRMS was modified to include a growing season calculation in this study. The growing season was examined for trends in the total length (annual), as well as changes in the timing of onset (spring) and the end (fall) of the growing season. The results showed an increase in the annual growing season length in all 14 basins, averaging 27–47 days for the three emission scenarios. The change in the spring and fall growing season onset and end varied across the 14 basins, with larger increases in the total length of the growing season occurring in the mountainous regions and smaller increases occurring in the Midwest, Northeast, and Southeast regions. The Clear Creek basin, 1 of the 14 basins in this study, was evaluated to examine the growing season length determined by emission scenario, as compared to a growing season length fixed baseline condition. The Clear Creek basin showed substantial variation in hydrologic responses, including streamflow, as a result of growing season length determined by emission scenario.

  13. Meteorological determinants of growing season onset in grassland

    NASA Astrophysics Data System (ADS)

    Orescanin, B.; Denning, S.; Baker, I. T.; Hanan, N. P.

    2012-12-01

    The exchange of the trace gases between the land and atmosphere is highly influenced by vegetation. Therefore, the representation of phenological properties in global carbon models plays a key role in understanding and predicting the global carbon cycle. Phenological parameters such as Leaf Area Index (LAI) and fraction of photosynthetically active radiation absorbed (fPAR) are often calculated or estimated based on remote sensing measurements, which can be biased by clouds, aerosols, or snow. Alternatively, we can prognose vegetation phenology through the use of models that predict vegetation status based on meteorological conditions. Here our goal is to provide better understanding of carbon dynamics as a function of phenological parameters and their dependence on meteorological forcing and also in the future we plan to estimate these parameters using data assimilation methodology. We evaluate phenological characteristics and their influence on carbon dynamics at Kruger National Park grassland site. Modeled carbon flux, as a function of prognosed phenological state is confronted with data from flux tower. By re-evaluating and better adjusting specific contributors to the growth season index (GSI) equation, we develop better understanding for prognostic phenology. These differences in phenology are reflected in modeled fluxes of energy, moisture, and carbon.

  14. Effects of seasonal snow on the growing season of temperate vegetation in China.

    PubMed

    Yu, Zhen; Liu, Shirong; Wang, Jingxin; Sun, Pengsen; Liu, Weiguo; Hartley, Damon S

    2013-07-01

    Variations in seasonal snowfall regulate regional and global climatic systems and vegetation growth by changing energy budgets of the lower atmosphere and land surface. We investigated the effects of snow on the start of growing season (SGS) of temperate vegetation in China. Across the entire temperate region in China, the winter snow depth increased at a rate of 0.15 cm yr(-1) (P = 0.07) during the period 1982-1998, and decreased at a rate of 0.36 cm yr(-1) (P = 0.09) during the period 1998-2005. Correspondingly, the SGS advanced at a rate of 0.68 day yr(-1) (P < 0.01) during 1982-1998, and delayed at a rate of 2.13 day yr(-1) (P = 0.07) during 1998-2005, against a warming trend throughout the entire study period of 1982-2005. Spring air temperature strongly regulated the SGS of both deciduous broad-leaf and coniferous forests, whereas the winter snow had a greater impact on the SGS of grassland and shrubs. Snow depth variation combined with air temperature contributed to the variability in the SGS of grassland and shrubs, as snow acted as an insulator and modulated the underground thermal conditions. In addition, differences were seen between the impacts of winter snow depth and spring snow depth on the SGS; as snow depths increased, the effect associated went from delaying SGS to advancing SGS. The observed thresholds for these effects were snow depths of 6.8 cm (winter) and 4.0 cm (spring). The results of this study suggest that the response of the vegetation's SGS to seasonal snow change may be attributed to the coupling effects of air temperature and snow depth associated with the underground thermal conditions.

  15. Effects of seasonal snow on the growing season of temperate vegetation in China.

    PubMed

    Yu, Zhen; Liu, Shirong; Wang, Jingxin; Sun, Pengsen; Liu, Weiguo; Hartley, Damon S

    2013-07-01

    Variations in seasonal snowfall regulate regional and global climatic systems and vegetation growth by changing energy budgets of the lower atmosphere and land surface. We investigated the effects of snow on the start of growing season (SGS) of temperate vegetation in China. Across the entire temperate region in China, the winter snow depth increased at a rate of 0.15 cm yr(-1) (P = 0.07) during the period 1982-1998, and decreased at a rate of 0.36 cm yr(-1) (P = 0.09) during the period 1998-2005. Correspondingly, the SGS advanced at a rate of 0.68 day yr(-1) (P < 0.01) during 1982-1998, and delayed at a rate of 2.13 day yr(-1) (P = 0.07) during 1998-2005, against a warming trend throughout the entire study period of 1982-2005. Spring air temperature strongly regulated the SGS of both deciduous broad-leaf and coniferous forests, whereas the winter snow had a greater impact on the SGS of grassland and shrubs. Snow depth variation combined with air temperature contributed to the variability in the SGS of grassland and shrubs, as snow acted as an insulator and modulated the underground thermal conditions. In addition, differences were seen between the impacts of winter snow depth and spring snow depth on the SGS; as snow depths increased, the effect associated went from delaying SGS to advancing SGS. The observed thresholds for these effects were snow depths of 6.8 cm (winter) and 4.0 cm (spring). The results of this study suggest that the response of the vegetation's SGS to seasonal snow change may be attributed to the coupling effects of air temperature and snow depth associated with the underground thermal conditions. PMID:23532953

  16. A comparison of growing season indices for the Greater Baltic Area.

    PubMed

    Walther, A; Linderholm, H W

    2006-11-01

    Predictions of the effects of global warming suggest that climate change may have large impacts on ecosystems. The length of the growing season is predicted to increase in response to increasing global temperatures. The object of this study was to evaluate different indices used for calculating the thermal growing season for the Greater Baltic Area (GBA). We included established indices of growing season start, end and length, as well as new and modified indices. Based on the results, the GBA can be divided into a maritime western part and a more continental eastern part, with the western part reacting more sensitively to the use of different indices. The eastern part is more stable, but even here the index-to-index differences are large. It was found that including or excluding a frost criterion had a significant influence on the initiation of the growing season in the western, maritime, parts of the GBA. Frost has not the same importance for the end of the growing season. However, some end indices can result in a "never ending" growing season. When looking at twentieth century trends in growing season parameters, it was found that, when averaged over the whole GBA, there was little difference in trends depending on the indices used. The general mean trend in the GBA for the twentieth century discloses an earlier onset of c. 12 days, a delayed end of c. 8 days and consequently a lengthening of the growing season of about 20 days.

  17. The Effect of Agricultural Growing Season Change on Market Prices in Africa

    NASA Technical Reports Server (NTRS)

    deBeurs, K.M.; Brown, M. E.

    2013-01-01

    to plan effective adaptation strategies. Remote sensing data can also provide some understanding of the spatial extent of these changes and whether they are likely to continue. Given the agricultural nature of most economies on the African continent, agricultural production continues to be a critical determinant of both food security and economic growth (Funk and Brown, 2009). Crop phenological parameters, such as the start and end of the growing season, the total length of the growing season, and the rate of greening and senescence are important for planning crop management, crop diversification, and intensification. The World Food Summit of 1996 defined food security as: "when all people at all times have access to sufficient, safe, nutritious food to maintain a healthy and active life". Food security roughly depends on three factors: 1) availability of food; 2) access to food and 3) appropriate use of food, as well as adequate water and sanitation. The first factor is dependent on growing conditions and weather and climate. In a previous paper we have investigated this factor by evaluating the effect of large scale climate oscillation on land surface phenology (Brown et al., 2010). We found that all areas in Africa are significantly affected by at least one type of large scale climate oscillations and concluded that these somewhat predictable oscillations could perhaps be used to forecast agricultural production. In addition, we have evaluated changes in agricultural land surface phenology over time (Brown et al., 2012). We found that land surface phenology models, which link large-scale vegetation indices with accumulated humidity, could successfully predict agricultural productivity in several countries around the world. In this chapter we are interested in the effect of variability in peak timing of the growing season, or phenology, on the second factor of food security, food access. In this chapter we want to determine if there is a link between market prices

  18. Reflectance and internal structure of leaves from several crops during a growing season.

    NASA Technical Reports Server (NTRS)

    Sinclair, T. R.; Hoffer, R. M.; Schreiber, M. M.

    1971-01-01

    Measurements of spectral reflectance characteristics during a growing season of leaves from six crops are reported. These crops include soybeans, wheat, oats, sorghum, corn, and sudangrass. The characteristics measured are related to changes in leaf structure and water content.

  19. Reserves accumulated in non-photosynthetic organs during the previous growing season drive plant defenses and growth in aspen in the subsequent growing season.

    PubMed

    Najar, Ahmed; Landhäusser, Simon M; Whitehill, Justin G A; Bonello, Pierluigi; Erbilgin, Nadir

    2014-01-01

    Plants store non-structural carbohydrates (NSC), nitrogen (N), as well as other macro and micronutrients, in their stems and roots; the role of these stored reserves in plant growth and defense under herbivory pressure is poorly understood, particularly in trees. Trembling aspen (Populus tremuloides) seedlings with different NSC and N reserves accumulated during the previous growing season were generated in the greenhouse. Based on NSC and N contents, seedlings were assigned to one of three reserve statuses: Low N-Low NSC, High N-Medium NSC, or High N-High NSC. In the subsequent growing season, half of the seedlings in each reserve status was subjected to defoliation by forest tent caterpillar (Malacosoma disstria) while the other half was left untreated. Following defoliation, the effect of reserves was measured on foliar chemistry (N, NSC) and caterpillar performance (larval development). Due to their importance in herbivore feeding, we also quantified concentrations of phenolic glycoside compounds in foliage. Seedlings in Low N-Low NSC reserve status contained higher amounts of induced phenolic glycosides, grew little, and supported fewer caterpillars. In contrast, aspen seedlings in High N-Medium or High NSC reserve statuses contained lower amounts of induced phenolic glycosides, grew faster, and some of the caterpillars which fed on these seedlings developed up to their fourth instar. Furthermore, multiple regression analysis indicated that foliar phenolic glycoside concentration was related to reserve chemistry (NSC, N). Overall, these results demonstrate that reserves accumulated during the previous growing season can influence tree defense and growth in the subsequent growing season. Additionally, our study concluded that the NSC/N ratio of reserves in the previous growing season represents a better measure of resources available for use in defense and growth than the foliar NSC/N ratios.

  20. Early and late seasonal carbon sequestration and allocation in larch trees growing on permafrost in Central Siberia

    NASA Astrophysics Data System (ADS)

    Masyagina, Oxana; Prokushkin, Anatoly; Kirdyanov, Alexander; Artyukhov, Aleksey; Udalova, Tatiana; Senchenkov, Sergey; Rublev, Aleksey

    2014-05-01

    Despite large geographic extent of deciduous conifer species Larix gmelinii, its seasonal photosynthetic activity and translocation of photoassimilated carbon within a tree remain poorly studied. To get better insight into productivity of larch trees growing on permafrost soils in Siberian larch biome we aimed to analyze dynamics of foliage parameters (i.e. leaf area, biomass, %N, %P etc.), seasonal dynamics of photosynthetic activity and apply whole tree labeling by 13CO2, which is powerful and effective tool for tracing newly developed assimilates translocation to tissues and organs of a tree (Kagawa et al., 2006; Keel et al., 2012). Experimental plot has been established in mature 105 year-old larch stand located within the continuous permafrost area near Tura settlement (Central Siberia, 64o17'13" N, 100o11'55" E, 148 m a.s.l.). Trees selected for experiments represented mean tree of the stand. Measurements of seasonal photosynthetic activity and foliar biomass sampling were arranged from early growing season (June 8, 2013) until yellowing and senescence of needles on September 17, 2013. Labeling by 13C in whole tree chamber was conducted by three pulses ([CO2]max ≤ 2,500 ppmv, 13CO2 (30% v/v)) at the early (June) and late (August) phase of growing season for different trees in 3 replicates each time. Both early season and late season labeling experiments demonstrated high rate of 13CO2 assimilation and respective enrichment of needle tissues by 13C: δ13C increased from -28.7 up to +670‰ just after labeling. However, there was distinct post-labeling dynamics of needle δ13C among two seasonal experiments. At the early season 13C depletion in labeled needles was slower, and δ13C approached after 40 days ca. +110 ‰ and remained constant till senescence. In the late season (August) needles were losing labeled C with much faster rate and approached only +1.5 ‰ upon senescence (28 days exposition). These findings suggest that in early season ca. 20% of

  1. Large-scale variations in the vegetation growing season and annual cycle of atmospheric CO2 at high northern latitudes from 1950 to 2011.

    PubMed

    Barichivich, Jonathan; Briffa, Keith R; Myneni, Ranga B; Osborn, Timothy J; Melvin, Thomas M; Ciais, Philippe; Piao, Shilong; Tucker, Compton

    2013-10-01

    We combine satellite and ground observations during 1950-2011 to study the long-term links between multiple climate (air temperature and cryospheric dynamics) and vegetation (greenness and atmospheric CO(2) concentrations) indicators of the growing season of northern ecosystems (>45°N) and their connection with the carbon cycle. During the last three decades, the thermal potential growing season has lengthened by about 10.5 days (P < 0.01, 1982-2011), which is unprecedented in the context of the past 60 years. The overall lengthening has been stronger and more significant in Eurasia (12.6 days, P < 0.01) than North America (6.2 days, P > 0.05). The photosynthetic growing season has closely tracked the pace of warming and extension of the potential growing season in spring, but not in autumn when factors such as light and moisture limitation may constrain photosynthesis. The autumnal extension of the photosynthetic growing season since 1982 appears to be about half that of the thermal potential growing season, yielding a smaller lengthening of the photosynthetic growing season (6.7 days at the circumpolar scale, P < 0.01). Nevertheless, when integrated over the growing season, photosynthetic activity has closely followed the interannual variations and warming trend in cumulative growing season temperatures. This lengthening and intensification of the photosynthetic growing season, manifested principally over Eurasia rather than North America, is associated with a long-term increase (22.2% since 1972, P < 0.01) in the amplitude of the CO(2) annual cycle at northern latitudes. The springtime extension of the photosynthetic and potential growing seasons has apparently stimulated earlier and stronger net CO(2) uptake by northern ecosystems, while the autumnal extension is associated with an earlier net release of CO(2) to the atmosphere. These contrasting responses may be critical in determining the impact of continued warming on northern terrestrial ecosystems and the

  2. Higher northern latitude normalized difference vegetation index and growing season trends from 1982 to 1999

    NASA Technical Reports Server (NTRS)

    Tucker, C. J.; Slayback, D. A.; Pinzon, J. E.; Los, S. O.; Myneni, R. B.; Taylor, M. G.

    2001-01-01

    Normalized difference vegetation index data from the polar-orbiting National Oceanic and Atmospheric Administration meteorological satellites from 1982 to 1999 show significant variations in photosynthetic activity and growing season length at latitudes above 35 degrees N. Two distinct periods of increasing plant growth are apparent: 1982-1991 and 1992-1999, separated by a reduction from 1991 to 1992 associated with global cooling resulting from the volcanic eruption of Mt. Pinatubo in June 1991. The average May to September normalized difference vegetation index from 45 degrees N to 75 degrees N increased by 9% from 1982 to 1991, decreased by 5% from 1991 to 1992, and increased by 8% from 1992 to 1999. Variations in the normalized difference vegetation index were associated with variations in the start of the growing season of -5.6, +3.9, and -1.7 days respectively, for the three time periods. Our results support surface temperature increases within the same period at higher northern latitudes where temperature limits plant growth.

  3. 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

  4. Warming and elevated CO2 lead to longer growing season in temperate grassland

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Observational data over time suggest that as climate has warmed the growing season has lengthened, although experimental warming shortens early-growing species’ life cycles. Are other plant species living longer? We found that experimental warming in a temperate, semi-arid grassland led to earlier l...

  5. A Simulation of the Importance of Length of Growing Season and Canopy Functional Properties on the Seasonal Gross Primary Production of Temperate Alpine Meadows

    PubMed Central

    Baptist, Florence; Choler, Philippe

    2008-01-01

    Background and Aims Along snowmelt gradients, the canopies of temperate alpine meadows differ strongly in their structural and biochemical properties. Here, a study is made of the effects of these canopy dissimilarities combined with the snow-induced changes in length of growing season on seasonal gross primary production (GPP). Methods Leaf area index (LAI) and community-aggregated values of leaf angle and leaf nitrogen content were estimated for seven alpine plant canopies distributed along a marked snowmelt gradient, and these were used as input variables in a sun–shade canopy bulk-photosynthesis model. The model was validated for plant communities of early and late snowmelt sites by measuring the instantaneous CO2 fluxes with a canopy closed-chamber technique. A sensitivity analysis was conducted to estimate the relative impact of canopy properties and environmental factors on the daily and seasonal GPP. Key Results Carbon uptake was primarily related to the LAI and total canopy nitrogen content, but not to the leaf angle. For a given level of photosynthetically active radiation, CO2 assimilation was higher under overcast conditions. Sensitivity analysis revealed that increase of the length of the growing season had a higher effect on the seasonal GPP than a similar increase of any other factor. It was also found that the observed greater nitrogen content and larger LAI of canopies in late-snowmelt sites largely compensated for the negative impact of the reduced growing season. Conclusions The results emphasize the primary importance of snow-induced changes in length of growing season on carbon uptake in alpine temperate meadows. It was also demonstrated how using leaf-trait values of the dominants is a useful approach for modelling ecosystem carbon-cycle-related processes, particularly when continuous measurements of CO2 fluxes are technically difficult. The study thus represents an important step in addressing the challenge of using a plant functional

  6. Hurricane season could be active

    NASA Astrophysics Data System (ADS)

    Showstack, Randy

    Storm activity during the 2003 Atlantic hurricane season likely will be above average, the U.S. National Oceanic and Atmospheric Administration noted on 19 May.The outlook could include 11 to 15 tropical storms, as well as 6 to 9 hurricanes, of which 2 to 4 could be classified as major hurricanes rated as category 3 or higher on the Saffir-Simpson Hurricane Scale.

  7. Pan-Arctic linkages between snow accumulation and growing season air temperature, soil moisture and vegetation

    NASA Astrophysics Data System (ADS)

    Luus, K. A.; Gel, Y.; Lin, J. C.; Kelly, R. E. J.; Duguay, C. R.

    2013-01-01

    Arctic field studies have indicated that the air temperature, soil moisture and vegetation at a site influence the quantity of snow accumulated, and that snow accumulation can alter growing season soil moisture and vegetation. Climate change is predicted to bring about warmer air temperatures, greater snow accumulation and northward movements of the shrub and tree lines. Understanding the response of northern environments to changes in snow and growing season land surface characteristics requires: (1) insights into the present-day linkages between snow and growing season land surface characteristics; and (2) the ability to continue to monitor these associations over time across the vast pan-Arctic. The objective of this study was therefore to examine the pan-Arctic (north of 60° N) linkages between two temporally distinct data products created from AMSR-E satellite passive microwave observations: GlobSnow snow water equivalent, and NTSG (growing season air temperature, soil moisture and vegetation transmissivity). Due to the complex and interconnected nature of processes determining snow and growing season land surface characteristics, these associations were analyzed using the modern non-parametric technique of Alternating Conditional Expectations (ACE), as this approach does not impose a predefined analytic form. Findings indicate that regions with lower vegetation transmissivity (more biomass) at the start and end of the growing season tend to accumulate less snow at the start and end of the snow season, possibly due to interception and shading. Warmer air temperatures at the start and end of the growing season were associated with diminished snow accumulation at the start and end of the snow season. High latitude sites with warmer mean annual growing season temperatures tended to accumulate more snow, probably due to the greater availability of water vapor for snow season precipitation at warmer locations. Regions with drier soils preceding snow onset tended

  8. Timing and duration of European larch growing season along altitudinal gradients in the Swiss Alps.

    PubMed

    Moser, Lea; Fonti, Patrick; Büntgen, Ulf; Esper, Jan; Luterbacher, Jürg; Franzen, Julia; Frank, David

    2010-02-01

    The 2007 European larch (Larix decidua Mill.) growing season was monitored along two elevational transects in the Lötschental valley in the Swiss Alps. Phenological observations and weekly microcore sampling of 28 larch trees were conducted between April and October 2007 at seven study sites regularly spaced from 1350 to 2150 m a.s.l. on northwest- and southeast-facing slopes. The developmental stages of nearly 75,000 individual cells assessed on 1200 thin sections were used to investigate the links between the trees' thermal regimes and growth phases including the beginning and ending of cell enlargement, wall thickening and maturation of the stem wood. Needles appeared approximately 3-4 weeks earlier than stem growth. The duration of ring formation lasted from mid-May to the end of October, with the length of the growing season decreasing along elevation from 137 to 101 days. The onset of the different growing seasons changed by 3-4 days per 100 m elevation; the ending of the growing season, however, appeared minimally related to altitude. If associated with the monitored altitudinal lapse rate of -0.5 degrees C per 100 m, these results translate into a lengthening of the growing season by approximately 7 days per degree Celsius. This study provides new data on the timing and duration of basic growth processes and contributes to quantification of the impacts of global warming on tree growth and productivity.

  9. Growing season and spatial variations of carbon fluxes of Arctic and boreal ecosystems in Alaska (USA).

    PubMed

    Ueyama, Masahito; Iwata, Hiroki; Harazono, Yoshinobu; Euskirchen, Eugénie S; Oechel, Walter C; Zona, Donatella

    2013-12-01

    To better understand the spatial and temporal dynamics of CO2 exchange between Arctic ecosystems and the atmosphere, we synthesized CO2 flux data, measured in eight Arctic tundra and five boreal ecosystems across Alaska (USA) and identified growing season and spatial variations of the fluxes and environmental controlling factors. For the period examined, all of the boreal and seven of the eight Arctic tundra ecosystems acted as CO2 sinks during the growing season. Seasonal patterns of the CO2 fluxes were mostly determined by air temperature, except ecosystem respiration (RE) of tundra. For the tundra ecosystems, the spatial variation of gross primary productivity (GPP) and net CO2 sink strength were explained by growing season length, whereas RE increased with growing degree days. For boreal ecosystems, the spatial variation of net CO2 sink strength was mostly determined by recovery of GPP from fire disturbance. Satellite-derived leaf area index (LAI) was a better index to explain the spatial variations of GPP and NEE of the ecosystems in Alaska than were the normalized difference vegetation index (NDVI) and enhanced vegetation index (EVI). Multiple regression models using growing degree days, growing season length, and satellite-derived LAI explained much of the spatial variation in GPP and net CO2 exchange among the tundra and boreal ecosystems. The high sensitivity of the sink strength to growing season length indicated that the tundra ecosystem could increase CO2 sink strength under expected future warming, whereas ecosystem compositions associated with fire disturbance could play a major role in carbon release from boreal ecosystems.

  10. Effects of chronic doses of ozone on loblolly pine: Photosynthetic characteristics in the third growing season

    SciTech Connect

    Sasek, T.W.; Richardson, C.J. )

    1989-09-01

    Gas exchange characteristics of loblolly pine seedlings were measured in the third growing season of ozone fumigations to determine the effects of long-term ozone exposure on photosynthetic capacity. Light and CO{sub 2} response curves indicated significant decreases of 21% and 27%, respectively, in light-saturated and CO{sub 2}-saturated photosynthetic capacities at 2 {times} ambient ozone compared to charcoal-filtered (CF) air, approximately 0.5 {times} ambient ozone. Differences in the response curves suggest changes in light-harvesting and biochemical efficiencies as well as changes in the activity of RuBP carboxylase and the regeneration rate of RuBP. Chlorophyll and carotenoid conditions per unit leaf area were decreased at the high ozone treatment in older flushes. Stomatal resistance limited photosynthesis by about 29% in both CF and 2 {times} ambient ozone treated plants, suggesting that chronic ozone exposure did not affect stomatal control in loblolly pine.

  11. Nitrogen and phosphorus leaching from growing season versus year-round application of wastewater on seasonally frozen lands.

    PubMed

    Zvomuya, Francis; Rosen, Carl J; Gupta, Satish C

    2006-01-01

    Land application of wastewater has become an important disposal option for food-processing plants operating year-round. However, there are concerns about nutrient leaching from winter wastewater application on frozen soils. In this study, P and N leaching were compared between nongrowing season application of tertiary-treated wastewater plus growing season application of partially treated wastewater (NGS) vs. growing season application of partially treated wastewater (GS) containing high levels of soil P. As required by the Minnesota Pollution Control Agency (MPCA), the wastewater applied to the NGS fields during October through March was treated such that it contained < or =6 mg L(-1) total phosphorus (TP), < or =10 mg L(-1) NO3-N, and < or =20 mg L(-1) total Kjeldahl nitrogen (TKN). The only regulation for wastewater application during the growing season (April through September) was that cumulatively it did not exceed the agronomic N requirements of the crop in any sprayfield. Application of tertiary-treated wastewater during the nongrowing season plus partially treated wastewater during the growing season did not significantly increase NO3-N leaching compared with growing season application of nonregulated wastewater. However, median TP concentration in leachate was significantly higher from the NGS (3.56 mg L(-1)) than from the GS sprayfields (0.52 mg L(-1)) or nonirrigated sites (0.52 mg L(-1)). Median TP leaching loss was also significantly higher from the NGS sprayfields (57 kg ha(-1)) than from the GS (7.4 kg ha(-1)) or control sites (6.9 kg ha(-1)). This was mainly due to higher hydraulic loading from winter wastewater application and limited or no crop P uptake during winter. Results from this study indicate that winter application of even low P potato-processing wastewater to high P soils can accelerate P leaching. We conclude that the regulation of winter wastewater application on frozen soils should be based on wastewater P concentration and

  12. Time constraints in temperate-breeding species: influence of growing season length on reproductive strategies

    USGS Publications Warehouse

    Gurney, K. E. B.; Clark, Russell G.; Slattery, Stuart; Smith-Downey, N. V.; Walker, Jordan I.; Armstrong, L.M.; Stephens, S.E.; Petrula, Michael J.; Corcoran, R.M.; Martin, K.; Degroot, K.A.; Brook, Rodney W.; Afton, Alan; Cutting, K.; Warren, J.M.; Fournier, M.; Koons, David N.

    2011-01-01

    Organisms that reproduce in temperate regions have limited time to produce offspring successfully, and this constraint is expected to be more pronounced in areas with short growing seasons. Information concerning how reproductive ecology of endotherms might be influenced by growing season length (GSL) is rare, and species that breed over a broad geographic range provide an opportunity to study the effects of time constraints on reproductive strategies. We analyzed data from a temperate-breeding bird, the lesser scaup Aythya affinis; hereafter scaup, collected at eight sites across a broad gradient of GSL to evaluate three hypotheses related to reproductive compensation in response to varying time constraints. Clutch initiation date in scaup was unaffected by GSL and was unrelated to latitude; spring thaw dates had a marginal impact on timing of breeding. Clutch size declined during the nesting season, as is reported frequently in bird species, but was also unaffected by GSL. Scaup do not appear to compensate for shorter growing seasons by more rapidly reducing clutch size. This study demonstrates that this species is remarkably consistent in terms of timing of breeding and clutch size, regardless of growing season characteristics. Such inflexibility could make this species particularly sensitive to environmental changes that affect resource availabilities.

  13. Time constraints in temperate-breeding species: Influence of growing season length on reproductive strategies

    USGS Publications Warehouse

    Gurney, K. E. B.; Clark, R.G.; Slattery, S.M.; Smith-Downey, N. V.; Walker, J.; Armstrong, L.M.; Stephens, S.E.; Petrula, M.; Corcoran, R.M.; Martin, K.H.; Degroot, K.A.; Brook, Rodney W.; Afton, A.D.; Cutting, K.; Warren, J.M.; Fournier, M.; Koons, D.N.

    2011-01-01

    Organisms that reproduce in temperate regions have limited time to produce offspring successfully, and this constraint is expected to be more pronounced in areas with short growing seasons. Information concerning how reproductive ecology of endotherms might be influenced by growing season length (GSL) is rare, and species that breed over a broad geographic range provide an opportunity to study the effects of time constraints on reproductive strategies. We analyzed data from a temperate-breeding bird, the lesser scaup Aythya affinis; hereafter scaup, collected at eight sites across a broad gradient of GSL to evaluate three hypotheses related to reproductive compensation in response to varying time constraints. Clutch initiation date in scaup was unaffected by GSL and was unrelated to latitude; spring thaw dates had a marginal impact on timing of breeding. Clutch size declined during the nesting season, as is reported frequently in bird species, but was also unaffected by GSL. Scaup do not appear to compensate for shorter growing seasons by more rapidly reducing clutch size. This study demonstrates that this species is remarkably consistent in terms of timing of breeding and clutch size, regardless of growing season characteristics. Such inflexibility could make this species particularly sensitive to environmental changes that affect resource availabilities. ?? 2011 The Authors. Ecography ?? 2011 Ecography.

  14. Population genetics of freeze tolerance among natural populations of Populus balsamifera across the growing season.

    PubMed

    Menon, Mitra; Barnes, William J; Olson, Matthew S

    2015-08-01

    Protection against freeze damage during the growing season influences the northern range limits of plants. Freeze tolerance and freeze avoidance are the two major freeze resistance strategies. Winter survival strategies have been extensively studied in perennials, but few have addressed them and their genetic basis during the growing season. We examined intraspecific phenotypic variation in freeze resistance of Populus balsamifera across latitude and the growing season. To investigate the molecular basis of this variation, we surveyed nucleotide diversity and examined patterns of gene expression in the poplar C-repeat binding factor (CBF) gene family. Foliar freeze tolerance exhibited latitudinal and seasonal variation indicative of natural genotypic variation. CBF6 showed signatures of recent selective sweep. Of the 46 SNPs surveyed across the six CBF homologs, only CBF2_619 exhibited latitudinal differences consistent with increased freeze tolerance in the north. All six CBF genes were cold inducible, but showed varying patterns of expression across the growing season. Some Poplar CBF homologs exhibited patterns consistent with historical selection and clinal variation in freeze tolerance documented here. However, the CBF genes accounted for only a small amount of the variation, indicating that other genes in this and other molecular pathways likely play significant roles in nature.

  15. Determination of Spring Onset and Growing Season Duration using Satellite Measurements

    NASA Technical Reports Server (NTRS)

    Min, Q.; Lin, Bing

    2006-01-01

    An integrated approach to retrieve microwave emissivity difference vegetation index (EDVI) over land regions has been developed from combined multi-platform/multi-sensor satellite measurements, including SSM/I measurements. A possible relationship of the remotely sensed EDVI and the leaf physiology of canopy is exploited at the Harvard Forest site for two growing seasons. This study finds that the EDVI is sensitive to leaf development through vegetation water content of the crown layer of the forest canopy, and has demonstrated that the spring onset and growing season duration can be determined accurately from the time series of satellite estimated EDVI within uncertainties about 3 and 7 days for spring onsets and growing season duration, respectively, compared to in-situ observations. The leaf growing stage may also be quantitatively monitored by a normalized EDVI. Since EDVI retrievals from satellite are generally possible during both daytime and nighttime under non-rain conditions, the EDVI technique studied here may provide higher temporal resolution observations for monitoring the onset of spring and the duration of growing season compared to currently operational satellite methods.

  16. The effect of timing of growing season drought on flowering of a dominant C4 grass.

    PubMed

    Dietrich, John D; Smith, Melinda D

    2016-06-01

    Timing of precipitation is equally important as amount for determining ecosystem function, especially aboveground net primary productivity (ANPP), in a number of ecosystems. In tallgrass prairie of the Central Plains of North America, grass flowering stalks of dominant C4 grasses, such as Andropogon gerardii, can account for more than 70 % of ANPP, or almost none of it, as the number of flowering stalks produced is highly variable. Although growing season precipitation amount is important for driving variation in flowering stalk production, it remains unknown whether there are critical periods within the growing season in which sufficient rainfall must occur to allow for flowering. The effect of timing of rainfall deficit (drought) on flowering of A. gerardii, was tested by excluding rainfall during three periods within the growing season (starting in mid-April, mid-May and mid-June). Mid-summer drought (starting in mid-June) strongly reduced the flowering rate (e.g., density and biomass) of A. gerardii (e.g., as high as 94 % compared to the control), suggesting flowering is highly sensitive to precipitation at this time. This effect appeared to be related to plant water status at the time of flowering stalk initiation, rather than an indirect consequence of reduced C assimilation. Our results suggest that increased frequency of growing season drought forecast with climate change could reduce sexual reproduction in this dominant grass species, particularly if it coincides with timing of flowering stalk initiation, with important implications for ecosystem functioning.

  17. USDA Cranberry Entomology Laboratory (CEL) research priorities in the 2016 growing season

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Research priorities during the 2016 growing season will be focused on 1) discovery and screening of native WI nematodes as bio-control agents, and 2) continued refinement of the drone-deployed mating disruption system. Extramural funding will be needed for both, and the degree of funding will dictat...

  18. Diurnal patterns of gas-exchange and metabolic pools in tundra plants during three phases of the arctic growing season

    PubMed Central

    Patankar, Rajit; Mortazavi, Behzad; Oberbauer, Steven F; Starr, Gregory

    2013-01-01

    Arctic tundra plant communities are subject to a short growing season that is the primary period in which carbon is sequestered for growth and survival. This period is often characterized by 24-h photoperiods for several months a year. To compensate for the short growing season tundra plants may extend their carbon uptake capacity on a diurnal basis, but whether this is true remains unknown. Here, we examined in situ diurnal patterns of physiological activity and foliar metabolites during the early, mid, and late growing season in seven arctic species under light-saturated conditions. We found clear diurnal patterns in photosynthesis and respiration, with midday peaks and midnight lulls indicative of circadian regulation. Diurnal patterns in foliar metabolite concentrations were less distinct between the species and across seasons, suggesting that metabolic pools are likely governed by proximate external factors. This understanding of diurnal physiology will also enhance the parameterization of process-based models, which will aid in better predicting future carbon dynamics for the tundra. This becomes even more critical considering the rapid changes that are occurring circumpolarly that are altering plant community structure, function, and ultimately regional and global carbon budgets. PMID:23467719

  19. Diurnal patterns of gas-exchange and metabolic pools in tundra plants during three phases of the arctic growing season.

    PubMed

    Patankar, Rajit; Mortazavi, Behzad; Oberbauer, Steven F; Starr, Gregory

    2013-02-01

    Arctic tundra plant communities are subject to a short growing season that is the primary period in which carbon is sequestered for growth and survival. This period is often characterized by 24-h photoperiods for several months a year. To compensate for the short growing season tundra plants may extend their carbon uptake capacity on a diurnal basis, but whether this is true remains unknown. Here, we examined in situ diurnal patterns of physiological activity and foliar metabolites during the early, mid, and late growing season in seven arctic species under light-saturated conditions. We found clear diurnal patterns in photosynthesis and respiration, with midday peaks and midnight lulls indicative of circadian regulation. Diurnal patterns in foliar metabolite concentrations were less distinct between the species and across seasons, suggesting that metabolic pools are likely governed by proximate external factors. This understanding of diurnal physiology will also enhance the parameterization of process-based models, which will aid in better predicting future carbon dynamics for the tundra. This becomes even more critical considering the rapid changes that are occurring circumpolarly that are altering plant community structure, function, and ultimately regional and global carbon budgets.

  20. Temporal disparity in leaf chlorophyll content and leaf area index across a growing season in a temperate deciduous forest

    NASA Astrophysics Data System (ADS)

    Croft, H.; Chen, J. M.; Zhang, Y.

    2014-12-01

    Spatial and temporal variations in canopy structure and leaf biochemistry have considerable influence on fluxes of CO2, water and energy and nutrient cycling in vegetation. Two vegetation indices (VI), NDVI and Macc01, were used to model the spatio-temporal variability of broadleaf chlorophyll content and leaf area index (LAI) across a growing season. Ground data including LAI, hyperspectral leaf reflectance factors (400-2500 nm) and leaf chlorophyll content were measured across the growing season and satellite-derived canopy reflectance data was acquired for 33 dates at 1200 m spatial resolution. Key phenological information was extracted using the TIMESAT software. Results showed that LAI and chlorophyll start of season (SOS) dates were at day of year (DOY) 130 and 157 respectively, and total season duration varied by 57 days. The spatial variability of chlorophyll and LAI phenology was also analyzed at the landscape scale to investigate phenological patterns over a larger spatial extent. Whilst a degree of spatial variability existed, results showed that chlorophyll SOS lagged approximately 20-35 days behind LAI SOS, and the end of season (EOS) LAI dates were predominantly between 20 and 30 days later than chlorophyll EOS. The large temporal differences between VI-derived chlorophyll content and LAI has important implications for biogeochemical models using NDVI or LAI to represent the fraction of photosynthetically active radiation absorbed by a canopy, in neglecting to account for delays in chlorophyll production and thus photosynthetic capacity.

  1. Enhanced winter soil frost reduces methane emission during the subsequent growing season in a boreal peatland.

    PubMed

    Zhao, Junbin; Peichl, Matthias; Nilsson, Mats B

    2016-02-01

    Winter climate change may result in reduced snow cover and could, consequently, alter the soil frost regime and biogeochemical processes underlying the exchange of methane (CH4 ) in boreal peatlands. In this study, we investigated the short-term (1-3 years) vs. long-term (11 years) effects of intensified winter soil frost (induced by experimental snow exclusion) on CH4 exchange during the following growing season in a boreal peatland. In the first 3 years (2004-2006), lower CH4 emissions in the treatment plots relative to the control coincided with delayed soil temperature increase in the treatment plots at the beginning of the growing season (May). After 11 treatment years (in 2014), CH4 emissions were lower in the treatment plots relative to the control over the entire growing season, resulting in a reduction in total growing season CH4 emission by 27%. From May to July 2014, reduced sedge leaf area coincided with lower CH4 emissions in the treatment plots compared to the control. From July to August, lower dissolved organic carbon concentrations in the pore water of the treatment plots explained 72% of the differences in CH4 emission between control and treatment. In addition, greater Sphagnum moss growth in the treatment plots resulted in a larger distance between the moss surface and the water table (i.e., increasing the oxic layer) which may have enhanced the CH4 oxidation potential in the treatment plots relative to the control in 2014. The differences in vegetation might also explain the lower temperature sensitivity of CH4 emission observed in the treatment plots relative to the control. Overall, this study suggests that greater soil frost, associated with future winter climate change, might substantially reduce the growing season CH4 emission in boreal peatlands through altering vegetation dynamics and subsequently causing vegetation-mediated effects on CH4 exchange.

  2. Estimating the Sensitivity of CLM-Crop to Plant Date and Growing Season Length

    NASA Astrophysics Data System (ADS)

    Drewniak, B. A.; Kotamarthi, V. R.

    2012-12-01

    The Community Land Model (CLM), the land component of the Community Earth System Model (CESM), is designed to estimate the land surface response to climate through simulated vegetation phenology and soil carbon and nitrogen dynamics. Since human influences play a significant role shaping the land surface, the vegetation has been expanded to include agriculture (CLM-Crop) for three crop types: corn, soybean, and spring wheat. CLM-Crop parameters, which define crop phenology, are optimized against AmeriFlux observations of gross primary productivity, net ecosystem exchange, and stored biomass and carbon, for two sites in the U.S. growing corn and soybean. However, there is uncertainty in the measurements and using a small subset of data to determine model parameters makes validation difficult. In order to account for the differences in plant behavior across climate zones, an input dataset is used to define the planting dates and the length of the growing season. In order to improve model performance, and to understand the impacts of uncertainty from the input data, we evaluate the sensitivity of crop productivity and production against planting date and the length of the growing season. First, CLM-Crop is modified to establish plant date based on temperature trends for the previous 10-day period, constrained against the range of observed planting dates. This new climate-based model is compared with the standard fixed plant dates to determine how sensitive the model is to when seeding occurs, and how comparable the climate calculated plant dates are to the fixed dates. Next, the length of the growing season will be revised to account for an alternative climate. Finally, both the climate-based planting and new growth season will be simulated together. Results of the different model runs will be compared to the standard model and to observations to determine the importance of planting date and growing season length on crop productivity and yield.

  3. Enhanced winter soil frost reduces methane emission during the subsequent growing season in a boreal peatland.

    PubMed

    Zhao, Junbin; Peichl, Matthias; Nilsson, Mats B

    2016-02-01

    Winter climate change may result in reduced snow cover and could, consequently, alter the soil frost regime and biogeochemical processes underlying the exchange of methane (CH4 ) in boreal peatlands. In this study, we investigated the short-term (1-3 years) vs. long-term (11 years) effects of intensified winter soil frost (induced by experimental snow exclusion) on CH4 exchange during the following growing season in a boreal peatland. In the first 3 years (2004-2006), lower CH4 emissions in the treatment plots relative to the control coincided with delayed soil temperature increase in the treatment plots at the beginning of the growing season (May). After 11 treatment years (in 2014), CH4 emissions were lower in the treatment plots relative to the control over the entire growing season, resulting in a reduction in total growing season CH4 emission by 27%. From May to July 2014, reduced sedge leaf area coincided with lower CH4 emissions in the treatment plots compared to the control. From July to August, lower dissolved organic carbon concentrations in the pore water of the treatment plots explained 72% of the differences in CH4 emission between control and treatment. In addition, greater Sphagnum moss growth in the treatment plots resulted in a larger distance between the moss surface and the water table (i.e., increasing the oxic layer) which may have enhanced the CH4 oxidation potential in the treatment plots relative to the control in 2014. The differences in vegetation might also explain the lower temperature sensitivity of CH4 emission observed in the treatment plots relative to the control. Overall, this study suggests that greater soil frost, associated with future winter climate change, might substantially reduce the growing season CH4 emission in boreal peatlands through altering vegetation dynamics and subsequently causing vegetation-mediated effects on CH4 exchange. PMID:26452333

  4. Strong contribution of autumn phenology to changes in satellite-derived growing season length estimates across Europe (1982-2011).

    PubMed

    Garonna, Irene; de Jong, Rogier; de Wit, Allard J W; Mücher, Caspar A; Schmid, Bernhard; Schaepman, Michael E

    2014-11-01

    Land Surface Phenology (LSP) is the most direct representation of intra-annual dynamics of vegetated land surfaces as observed from satellite imagery. LSP plays a key role in characterizing land-surface fluxes, and is central to accurately parameterizing terrestrial biosphere-atmosphere interactions, as well as climate models. In this article, we present an evaluation of Pan-European LSP and its changes over the past 30 years, using the longest continuous record of Normalized Difference Vegetation Index (NDVI) available to date in combination with a landscape-based aggregation scheme. We used indicators of Start-Of-Season, End-Of-Season and Growing Season Length (SOS, EOS and GSL, respectively) for the period 1982-2011 to test for temporal trends in activity of terrestrial vegetation and their spatial distribution. We aggregated pixels into ecologically representative spatial units using the European Landscape Classification (LANMAP) and assessed the relative contribution of spring and autumn phenology. GSL increased significantly by 18-24 days decade(-1) over 18-30% of the land area of Europe, depending on methodology. This trend varied extensively within and between climatic zones and landscape classes. The areas of greatest growing-season lengthening were the Continental and Boreal zones, with hotspots concentrated in southern Fennoscandia, Western Russia and pockets of continental Europe. For the Atlantic and Steppic zones, we found an average shortening of the growing season with hotspots in Western France, the Po valley, and around the Caspian Sea. In many zones, changes in the NDVI-derived end-of-season contributed more to the GSL trend than changes in spring green-up, resulting in asymmetric trends. This underlines the importance of investigating senescence and its underlying processes more closely as a driver of LSP and global change.

  5. Arbuscular mycorrhizal fungal networks vary throughout the growing season and between successional stages.

    PubMed

    Bennett, Alison Elizabeth; Daniell, Tim John; Öpik, Maarja; Davison, John; Moora, Mari; Zobel, Martin; Selosse, Marc-André; Evans, Darren

    2013-01-01

    To date, few analyses of mutualistic networks have investigated successional or seasonal dynamics. Combining interaction data from multiple time points likely creates an inaccurate picture of the structure of networks (because these networks are aggregated across time), which may negatively influence their application in ecosystem assessments and conservation. Using a replicated bipartite mutualistic network of arbuscular mycorrhizal (AM) fungal-plant associations, detected using large sample numbers of plants and AM fungi identified through molecular techniques, we test whether the properties of the network are temporally dynamic either between different successional stages or within the growing season. These questions have never been directly tested in the AM fungal-plant mutualism or the vast majority of other mutualisms. We demonstrate the following results: First, our examination of two different successional stages (young and old forest) demonstrated that succession increases the proportion of specialists within the community and decreases the number of interactions. Second, AM fungal-plant mutualism structure changed throughout the growing season as the number of links between partners increased. Third, we observed shifts in associations between AM fungal and plant species throughout the growing season, potentially reflecting changes in biotic and abiotic conditions. Thus, this analysis opens up two entirely new areas of research: 1) identifying what influences changes in plant-AM fungal associations in these networks, and 2) what aspects of temporal variation and succession are of general importance in structuring bipartite networks and plant-AM fungal communities.

  6. Multi-trait Analysis of Agroclimate Variations During the Growing Season in East-Central Poland (1971-2005)

    NASA Astrophysics Data System (ADS)

    Radzka, Elżbieta; Rymuza, Katarzyna

    2015-04-01

    The work is based on meteorological data recorded by nine stations of the Institute of Meteorology and Water Management located in east-central Poland from 1971 to 2005. The region encompasses the North Podlasian Lowland and the South Podlasian Lowland. Average values of selected agroclimate indicators for the growing season were determined. Moreover, principal component analysis was conducted to indicate elements that exerted the greatest influence on the agroclimate. Also, cluster analysis was carried out to select stations with similar agroclimate. Ward method was used for clustering and the Euclidean distance was applied. Principal component analysis revealed that the agroclimate of east-central Poland was predominantly affected by climatic water balance, number of days of active plant growth, length of the farming period, and the average air temperature during the growing season (Apr-Sept). Based on the analysis, the region of east-central Poland was divided into two groups (areas) with different agroclimatic conditions. The first area comprized the following stations: Szepietowo and Białowieża located in the North Podlasian Lowland and Biała Podlaska situated in the northern part of the South Podlasian Lowland. This area was characterized by shorter farming periods and a lower average air temperature during the growing season. The other group included the remaining stations located in the western part of both the Lowlands which was warmer and where greater water deficits were recorded.

  7. 317/319 Phytoremediation site monitoring report - 2009 growing season : final report.

    SciTech Connect

    Negri, C .N.; Benda, P. L.; Gopalakrishnan, G.; Energy Systems

    2010-02-10

    In 1999, Argonne National Laboratory (Argonne) designed and installed a series of engineered plantings consisting of a vegetative cover system and approximately 800 hybrid poplars and willows rooting at various predetermined depths. The plants were installed using various methods including Applied Natural Science's TreeWell{reg_sign} system. The goal of the installation was to protect downgradient surface and groundwater by intercepting the contaminated groundwater with the tree roots, removing moisture from the upgradient soil area, reducing water infiltration, preventing soil erosion, degrading and/or transpiring the residual volatile organic compounds (VOCs), and removing tritium from the subsoil and groundwater. This report presents the results of the monitoring activities conducted by Argonne's Energy Systems (ES) Division in the growing season of 2009. Monitoring of the planted trees began soon after the trees were installed in 1999 and has been conducted every summer since then. As the trees grew and consolidated their growth into the contaminated soil and groundwater, their exposure to the contaminants was progressively shown through tissue sampling. During the 2009 sampling campaign, VOC concentrations found in the French Drain area were in general consistent with or slightly lower than the 2008 results. Additionally, closely repeated, stand wide analyses showed contaminant fluctuations that may indicate short-term contaminant depletion in the area of interest of roots. This data will be useful to determine short-term removal rate by the trees. As in previous years, levels in the Hydraulic Control Area were close to background levels except for a few exceptions.

  8. No increase in alpine snowbed productivity in response to experimental lengthening of the growing season.

    PubMed

    Baptist, F; Flahaut, C; Streb, P; Choler, P

    2010-09-01

    Climate change effects on snow cover and thermic regime in alpine tundra might lead to a longer growing season, but could also increase risks to plants from spring frost events. Alpine snowbeds, i.e. alpine tundra from late snowmelt sites, might be particularly susceptible to such climatic changes. Snowbed communities were grown in large monoliths for two consecutive years, under different manipulated snow cover treatments, to test for effects of early (E) and late (L) snowmelt on dominant species growth, plant functional traits, leaf area index (LAI) and aboveground productivity. Spring snow cover was reduced to assess the sensitivity of snowbed alpine species to severe early frost events, and dominant species freezing temperatures were measured. Aboveground biomass, productivity, LAI and dominant species growth did not increase significantly in E compared to L treatments, indicating inability to respond to an extended growing season. Edapho-climatic conditions could not account for these results, suggesting that developmental constraints are important in controlling snowbed plant growth. Impaired productivity was only detected when harsher and more frequent frost events were experimentally induced by early snowmelt. These conditions exposed plants to spring frosts, reaching temperatures consistent with the estimated freezing points of the dominant species ( approximately -10 degrees C). We conclude that weak plasticity in phenological response and potential detrimental effects of early frosts explain why alpine tundra from snowbeds is not expected to benefit from increased growing season length.

  9. Seasonal sap flow of four Salix varieties growing on the Solvay wastebeds in Syracuse, NY, USA.

    PubMed

    Mirck, Jaconette; Volk, Timothy A

    2010-01-01

    Sap flow of four shrub willow varieties was measured to study their potential use as an evapotranspiration (ET) cover on the Solvay wastebeds to reduce deep percolation and leaching of chloride. Stem and stand-level sap flow and crop coefficients (K(c)) were different among four willow varieties measured between early June and mid November 2006. Diameter and cross sectional area had a significant impact on stand level sap flow. Peak stand-level sap flow of 7 mm d(-1) occurred in June, due to coupling of the willow with the atmosphere, and not in July or August when peak LAI was measured. The coupling also resulted in high K(c) values of 3 in June and above 2 in October with an average of 1.1-1.3 for the entire season. Our measurements confirmed the potentials of shrub willow in ET cover applications in the northeastern USA. Total transpiration for the growing season ranged between 494 mm and 533 mm, which was about 45% of the precipitation in 2006. Our calculations showed a significant difference between peak season sap flow in June, July and August and sap flow over the course of the whole growing season, which showed the need for long-term measurements.

  10. Comparison of phenology models for predicting the onset of growing season over the Northern Hemisphere.

    PubMed

    Fu, Yang; Zhang, Haicheng; Dong, Wenjie; Yuan, Wenping

    2014-01-01

    Vegetation phenology models are important for examining the impact of climate change on the length of the growing season and carbon cycles in terrestrial ecosystems. However, large uncertainties in present phenology models make accurate assessment of the beginning of the growing season (BGS) a challenge. In this study, based on the satellite-based phenology product (i.e. the V005 MODIS Land Cover Dynamics (MCD12Q2) product), we calibrated four phenology models, compared their relative strength to predict vegetation phenology; and assessed the spatial pattern and interannual variability of BGS in the Northern Hemisphere. The results indicated that parameter calibration significantly influences the models' accuracy. All models showed good performance in cool regions but poor performance in warm regions. On average, they explained about 67% (the Growing Degree Day model), 79% (the Biome-BGC phenology model), 73% (the Number of Growing Days model) and 68% (the Number of Chilling Days-Growing Degree Day model) of the BGS variations over the Northern Hemisphere. There were substantial differences in BGS simulations among the four phenology models. Overall, the Biome-BGC phenology model performed best in predicting the BGS, and showed low biases in most boreal and cool regions. Compared with the other three models, the two-phase phenology model (NCD-GDD) showed the lowest correlation and largest biases with the MODIS phenology product, although it could catch the interannual variations well for some vegetation types. Our study highlights the need for further improvements by integrating the effects of water availability, especially for plants growing in low latitudes, and the physiological adaptation of plants into phenology models.

  11. Comparison of phenology models for predicting the onset of growing season over the Northern Hemisphere.

    PubMed

    Fu, Yang; Zhang, Haicheng; Dong, Wenjie; Yuan, Wenping

    2014-01-01

    Vegetation phenology models are important for examining the impact of climate change on the length of the growing season and carbon cycles in terrestrial ecosystems. However, large uncertainties in present phenology models make accurate assessment of the beginning of the growing season (BGS) a challenge. In this study, based on the satellite-based phenology product (i.e. the V005 MODIS Land Cover Dynamics (MCD12Q2) product), we calibrated four phenology models, compared their relative strength to predict vegetation phenology; and assessed the spatial pattern and interannual variability of BGS in the Northern Hemisphere. The results indicated that parameter calibration significantly influences the models' accuracy. All models showed good performance in cool regions but poor performance in warm regions. On average, they explained about 67% (the Growing Degree Day model), 79% (the Biome-BGC phenology model), 73% (the Number of Growing Days model) and 68% (the Number of Chilling Days-Growing Degree Day model) of the BGS variations over the Northern Hemisphere. There were substantial differences in BGS simulations among the four phenology models. Overall, the Biome-BGC phenology model performed best in predicting the BGS, and showed low biases in most boreal and cool regions. Compared with the other three models, the two-phase phenology model (NCD-GDD) showed the lowest correlation and largest biases with the MODIS phenology product, although it could catch the interannual variations well for some vegetation types. Our study highlights the need for further improvements by integrating the effects of water availability, especially for plants growing in low latitudes, and the physiological adaptation of plants into phenology models. PMID:25279567

  12. Changes of the spruce forest stand aerodynamic properties during ten growing seasons

    NASA Astrophysics Data System (ADS)

    Hurtalova, T.; Matejka, F.; Janous, D.; Czerny, R.

    2009-04-01

    Objective of this study was to quantify the influence of a young spruce forest stand on airflow and its aerodynamic characteristics during ten growing seasons. With this aim the wind speed profiles measured in and above investigated spruce stand during growing seasons, from May to October, 1998-2007 were analysed. Experimental site is situated on a mild slope with SW orientation in the locality Bílý Kříž (49o30'17'' N, 18o32'28'' E, 898-908 m a.s.l.), which is in the highest part of the Moravian-Silesian Beskydy Mts, Czech Republic. The experimental site consisting of two plots Fd and Fs with different tree density is created by the monoculture of young Norway spruce stand (Picea abies L., Karst) with age of 17 years in 1998. Each of these plots has the area of 2500 m2, density of 2600 trees/ha in Fd plot and 2400 trees/ha in Fs plot in 1998, and gradually 1652 trees/ha (Fd) and 1428 trees/ha (Fs) in 2007. The aerodynamic characteristics can be described by the roughness length (z0) and the zero plane displacement (d). The presented study aims to analyse the changes in d and z0 values for a young spruce forest stand during ten consecutive growing seasons, and to relate the aerodynamic properties of an air layer affected by this stand to its growth parameters. It is known, that the local terrain and structure of forest stand influenced the direction and power of the airflow, as well as the structure of vertical wind speed profiles. From the wind speed profile analysis it follows, that the investigated spruce stand was in an aerodynamic unsteady state and then d and z0 values vary also with the wind speed. During investigated seasons the mean seasonal z0 values ranged between 0.48 m and 1.32 m in Fd and the corresponding values in Fs plot varied between 0.41 m and 1.36 m. The mean seasonal d values varied between 0.60h and 0.76h in Fd, and 61h and 0.76h in Fs, h is mean stand height.

  13. Seasonal variation in muscle sympathetic nerve activity.

    PubMed

    Cui, Jian; Muller, Matthew D; Blaha, Cheryl; Kunselman, Allen R; Sinoway, Lawrence I

    2015-08-01

    Epidemiologic data suggest there are seasonal variations in the incidence of severe cardiac events with peak levels being evident in the winter. Whether autonomic indices including muscle sympathetic nerve activity (MSNA) vary with season remains unclear. In this report, we tested the hypothesis that resting MSNA varies with the seasons of the year with peak levels evident in the winter. We analyzed the supine resting MSNA in 60 healthy subjects. Each subject was studied during two, three, or four seasons (total 237 visits). MSNA burst rate in the winter (21.0 ± 6.8 burst/min, mean ± SD) was significantly greater than in the summer (13.5 ± 5.8 burst/min, P < 0.001), the spring (17.1 ± 9.0 burst/min, P = 0.03), and the fall (17.9 ± 7.7 burst/min, P = 0.002). There was no significant difference in MSNA for other seasonal comparisons. The results suggest that resting sympathetic nerve activity varies along the seasons, with peak levels evident in the winter. We speculate that the seasonal changes in sympathetic activity may be a contribution to the previously observed seasonal variations in cardiovascular morbidity and mortality. PMID:26265752

  14. Seasonal variation in muscle sympathetic nerve activity

    PubMed Central

    Cui, Jian; Muller, Matthew D; Blaha, Cheryl; Kunselman, Allen R; Sinoway, Lawrence I

    2015-01-01

    Epidemiologic data suggest there are seasonal variations in the incidence of severe cardiac events with peak levels being evident in the winter. Whether autonomic indices including muscle sympathetic nerve activity (MSNA) vary with season remains unclear. In this report, we tested the hypothesis that resting MSNA varies with the seasons of the year with peak levels evident in the winter. We analyzed the supine resting MSNA in 60 healthy subjects. Each subject was studied during two, three, or four seasons (total 237 visits). MSNA burst rate in the winter (21.0 ± 6.8 burst/min, mean ± SD) was significantly greater than in the summer (13.5 ± 5.8 burst/min, P < 0.001), the spring (17.1 ± 9.0 burst/min, P = 0.03), and the fall (17.9 ± 7.7 burst/min, P = 0.002). There was no significant difference in MSNA for other seasonal comparisons. The results suggest that resting sympathetic nerve activity varies along the seasons, with peak levels evident in the winter. We speculate that the seasonal changes in sympathetic activity may be a contribution to the previously observed seasonal variations in cardiovascular morbidity and mortality. PMID:26265752

  15. Fertilizer application timing influences greenhouse gas fluxes over a growing season.

    PubMed

    Phillips, Rebecca L; Tanaka, Donald L; Archer, David W; Hanson, Jon D

    2009-01-01

    Microbial production and consumption of greenhouse gases (GHG) is influenced by temperature and nutrients, especially during the first few weeks after agricultural fertilization. The effect of fertilization on GHG fluxes should occur during and shortly after application, yet data indicating how application timing affects both GHG fluxes and crop yields during a growing season are lacking. We designed a replicated (n = 5) field experiment to test for the short-term effect of fertilizer application timing on fluxes of methane (CH(4)), carbon dioxide (CO(2)), and nitrous oxide (N(2)O) over a growing season in the northern Great Plains. Each 0.30-ha plot was planted to maize (Zea mays L.) and treated similarly with the exception of fertilizer timing: five plots were fertilized with urea in early spring (1 April) and five plots were fertilized with urea in late spring (13 May). We hypothesized time-integrated fluxes over a growing season would be greater for the late-spring treatment, resulting in a greater net GHG flux, as compared to the early-spring treatment. Data collected on 59 dates and integrated over a 5-mo time course indicated CO(2) fluxes were greater (P < 0.0001) and CH(4) fluxes were lower (P < 0.05) for soils fertilized in late spring. Net GHG flux was also significantly affected by treatment, with 0.84 +/- 0.11 kg CO(2) equivalents m(-2) for early spring and 1.04 +/- 0.13 kg CO(2) equivalents m(-2) for late spring. Nitrous oxide fluxes, however, were similar for both treatments. Results indicate fertilizer application timing influences net GHG emissions in dryland cropping systems.

  16. Changing water availability during the African maize-growing season, 1979-2010

    NASA Astrophysics Data System (ADS)

    Estes, Lyndon D.; Chaney, Nathaniel W.; Herrera-Estrada, Julio; Sheffield, Justin; Caylor, Kelly K.; Wood, Eric F.

    2014-07-01

    Understanding how global change is impacting African agriculture requires a full physical accounting of water supply and demand, but accurate, gridded data on key drivers (e.g., humidity) are generally unavailable. We used a new bias-corrected meteorological dataset to analyze changes in precipitation (supply), potential evapotranspiration ({{E}_{p}}, demand), and water availability (expressed as the ratio P/{{E}_{p}}) in 20 countries (focusing on their maize-growing regions and seasons), between 1979 and 2010, and the factors driving changes in {{E}_{p}}. Maize-growing areas in Southern Africa, particularly South Africa, benefitted from increased water availability due in large part to demand declines driven primarily by declining net radiation, increasing vapor pressure, and falling temperatures (with no effect from changing windspeed), with smaller increases in supply. Sahelian zone countries in West Africa, as well as Ethiopia in East Africa, had strong increases in availability driven primarily by rainfall rebounding from the long-term Sahelian droughts, with little change or small reductions in demand. However, intra-seasonal supply variability generally increased in West and East Africa. Across all three regions, declining net radiation contributed downwards pressure on demand, generally over-riding upwards pressure caused by increasing temperatures, the regional effects of which were largest in East Africa. A small number of countries, mostly in or near East Africa (Tanzania and Malawi) experienced declines in water availability primarily due to decreased rainfall, but exacerbated by increasing demand. Much of the reduced water availability in East Africa occurred during the more sensitive middle part of the maize-growing season, suggesting negative consequences for maize production.

  17. Mean and inter-year variation of growing-season normalized difference vegetation index for the Sahel 1981-1989

    NASA Technical Reports Server (NTRS)

    Tucker, C. J.; Newcomb, W. W.; Los, S. O.; Prince, S. D.

    1991-01-01

    Images are presented that show the mean and coefficient of variation of nine years (1981-1989) of NOAA AVHRR normalized difference vegetation index (NDVI) data for the growing season (July-October) in Africa, north of the equator. The variation in the growing season NDVI is represented by the coefficient of variation image that shows the large variation in the Sahelian growing season between years. It is concluded that these images illustrate some aspects of the perspective being brought to regional and continental scale processes by coarse resolution satellite sensors and the potential of these sensors to provide consistent, long-term datasets.

  18. Does the start and end of the biological growing season respond independently to a changing climate?

    NASA Astrophysics Data System (ADS)

    Bolmgren, Kjell

    2016-04-01

    Adaptation of the biological growing season to a changing climatic requires that plants can adapt their phenology plastically or genetically to new conditions. Physiological and evolutionary constraints may, however, hamper such adaptations. Here, we study correlations between leafing out and autumn coloration phenology, that is, the start and end of the green growing season. In temperate, deciduous tree species the period with green leaves is more or less the same as the individual leaf's life span. General plant ecological strategy schemes suggest that the individual leaf's life span is one of the major dimensions evolutionary associated with other leaf and plant characteristics, including expensive investments in leaf nutrient content and leaf morphology. Leaf life span is thus considered highly conserved within evolutionary lineages. At the same time, local adaptation of leaf phenology to the length of the climatic growing season is common, both when it comes to leafing out cues and autumn senescence cues, suggesting that there are strong selection pressures and adaptability (plastic and/or genetic) to make use of the climatically defined growing season. We used a data set from a Swedish, national phenology network where volunteer observers recorded the start of leafing out defined as 'when the tree looks green from a distance' and the start of autumn leaf coloration as 'when 1/3 of the tree canopy had attained autumn colors'. In the subset used observations were made at 489 sites/farms between 1873-1922. We only included data when the observer at a site and year had recorded both spring leafing and autumn leaf coloration phenology on the same species. In total, the data set comprised 25'099 observations of 17 species. As the participants in the phenology monitoring network were volunteers, the data matrix has lots of missing data and unbalanced representation from different sites. We used linear mixed model analyses, including year as random factor, to analyse

  19. Mutation at the circadian clock gene EARLY MATURITY 8 adapts domesticated barley (Hordeum vulgare) to short growing seasons.

    PubMed

    Faure, Sebastien; Turner, Adrian S; Gruszka, Damian; Christodoulou, Vangelis; Davis, Seth J; von Korff, Maria; Laurie, David A

    2012-05-22

    The circadian clock is an autonomous oscillator that produces endogenous biological rhythms with a period of about 24 h. This clock allows organisms to coordinate their metabolism and development with predicted daily and seasonal changes of the environment. In plants, circadian rhythms contribute to both evolutionary fitness and agricultural productivity. Nevertheless, we show that commercial barley varieties bred for short growing seasons by use of early maturity 8 (eam8) mutations, also termed mat-a, are severely compromised in clock gene expression and clock outputs. We identified EAM8 as a barley ortholog of the Arabidopsis thaliana circadian clock regulator EARLY FLOWERING3 (ELF3) and demonstrate that eam8 accelerates the transition from vegetative to reproductive growth and inflorescence development. We propose that eam8 was selected as barley cultivation moved to high-latitude short-season environments in Europe because it allowed rapid flowering in genetic backgrounds that contained a previously selected late-flowering mutation of the photoperiod response gene Ppd-H1. We show that eam8 mutants have increased expression of the floral activator HvFT1, which is independent of allelic variation at Ppd-H1. The selection of independent eam8 mutations shows that this strategy facilitates short growth-season adaptation and expansion of the geographic range of barley, despite the pronounced clock defect.

  20. Growing season ecosystem and leaf-level gas exchange of an exotic and native semiarid bunchgrass.

    PubMed

    Hamerlynck, Erik P; Scott, Russell L; Moran, M Susan; Keefer, Timothy O; Huxman, Travis E

    2010-07-01

    The South African grass, Lehmann lovegrass (Eragrostis lehmanniana), may alter ecosystem processes across extensive semiarid grasslands and savannahs of western North America. We compared volumetric soil moisture (theta), total and green tissue leaf area index (LAI), ecosystem (i.e. whole-plant and soil), and leaf-level gas exchange of Lehmann lovegrass and the native bush muhly (Muhlenbergia porteri) over the 2008 monsoon season in a semiarid savanna in southern Arizona, USA, to see if these were consistent with high productivity associated with lovegrass invasive success. theta across 0-5 and 0-25 cm was higher while evapotranspiration (ET) was similar between lovegrass and bush muhly plots, except shortly after rainfall, when ET was 32-81% higher in lovegrass plots. Lehmann lovegrass had lower, quickly developing LAI with greater leaf proportions than bush muhly. When early season theta was high, net ecosystem CO(2) exchange (NEE) was similar, but as storm frequency and theta declined, NEE was more negative in lovegrass (-0.69 to -3.00 micromol m(-2) s(-1)) than bush muhly (+1.75 to -1.55 micromol m(-2) s(-1)). Ecosystem respiration (R (eco)) responded quickly to monsoon onset and late-season rains, and was lower in lovegrass (2.44-3.74 micromol m(-2) s(-1)) than bush muhly (3.60-5.3 micromol m(-2) s(-1)) across the season. Gross ecosystem photosynthesis (GEP) was greater in Lehmann lovegrass, concurrent with higher leaf-level photosynthesis and stomatal conductance. We conclude that canopy structure facilitates higher theta under Lehmann lovegrass, reducing phenological constraints and stomatal limitations to whole-plant carbon uptake through the short summer monsoon growing season.

  1. Season of testing and its effect on feed intake and efficiency in growing beef cattle.

    PubMed

    Mujibi, F D N; Moore, S S; Nkrumah, D J; Wang, Z; Basarab, J A

    2010-12-01

    This study sought to assess whether residual feed intake (RFI) calculated by regressing feed intake (DMI) on growth rate (ADG) and metabolic mid-BW in 3 different ways led to similar estimates of genetic parameters and variance components for young growing cattle tested for feed intake in fall and winter seasons. A total of 378 beef steers in 5 cohorts were fed a typical high energy feedlot diet and had free-choice access to feed and water. Feed intake data were collected in fall or winter seasons. Climate data were obtained from the University of Alberta Kinsella meteorological station and Vikings AGCM station. Individual animal RFI was obtained by either fitting a regression model to each test group separately (RFI(C)), fitting a regression model to pooled data consisting of all cohorts but including test group as a fixed effect (RFI(O)), or fitting a regression to pooled data with test group as a fixed effect but within seasonal (fall-winter or winter-spring) groups (RFI(S)). Two animal models (M1 and M2) that differed by the inclusion of fixed effects of test group or season, respectively, were used to evaluate RFI measurements. Feed intake was correlated with air temperature, relative humidity, solar radiation, and wind speed (-0.26, 0.23, 0.30, -0.14 for fall-winter and 0.31, -0.04, 0.14, 0.16 for winter-spring, respectively), but the nature and magnitude of the correlations were different for the 2 seasons. Single trait direct heritability, model likelihood, direct genetic variance, and EBV accuracy estimates were greatest for RFI(C) and least for RFI(O) for both M1 and M2 models. A significant genetic correlation was also observed between RFI(O) and ADG, but not for RFI(C) and RFI(S). Including a season effect (M2) in the genetic evaluation of RFI(O) resulted in the smallest heritability, model LogL, EBV accuracy, and largest residual variance estimates. These results, though not conclusive, suggest a possible effect of seasonality on feed intake and thus

  2. Long-term variations in phenological phases and growing season indexes in the Czech Republic

    NASA Astrophysics Data System (ADS)

    Mozny, M.; Potop, V.; Hajkova, L.; Bares, D.; Stalmacher, M.; Trnka, M.; Bartosova, L.; Zalud, Z.

    2012-04-01

    Phenological phases reflect weather conditions immediately prior to their onset and are therefore very important documentary record of the impact of climate on plants in a particular region. We analyze the results of phenological observations in the Czech Republic in the years 1931-2010. Air temperature increases were associated with an earlier onset of phenological phases; not just the beginning of the growing season but also the interval between successive phenological phases was shorter. Spatial variability of average phenophase onset were executed by GIS methods, the maps use horizontal resolutions of 500 meters. To quantify the rate and timing of changes in canopy development was utilized Growing Season Index (GSI), which was calculated from conventional meteorological measurements. Finally, we used the GSI index for producing global maps that distinguish regional differences in the current phenological development in the Czech Republic. GSI index can be used in modeling of CO2 exchange at the interface of biosphere and atmosphere. We gratefully acknowledge the support of the Ministry of education, youth and sports project OC10010, LD11401 and National Agency for Agriculture Research project Q191C054.

  3. Growing season carbon dioxide exchange in flooded non-mulching and non-flooded mulching cotton.

    PubMed

    Li, Zhi-guo; Zhang, Run-hua; Wang, Xiu-jun; Chen, Fang; Tian, Chang-yan

    2012-01-01

    There is much interest in the role that agricultural practices might play in sequestering carbon to help offset rising atmospheric CO₂ concentrations. However, limited information exists regarding the potential for increased carbon sequestration of different management strategies. The objective of this study was to quantify and contrast carbon dioxide exchange in traditional non-mulching with flooding irrigation (TF) and plastic film mulching with drip irrigation (PM) cotton (Gossypium hirsutum L.) fields in northwest China. Net primary productivity (NPP), soil heterotrophic respiration (R(h)) and net ecosystem productivity (NEP) were measured during the growing seasons in 2009 and 2010. As compared with TF, PM significantly increased the aboveground and belowground biomass and the NPP (340 g C m⁻² season⁻¹) of cotton, and decreased the R(h) (89 g C m⁻² season⁻¹) (p<0.05). In a growing season, PM had a higher carbon sequestration in terms of NEP of ∼ 429 g C m⁻² season⁻¹ than the TF. These results demonstrate that conversion of this type of land use to mulching practices is an effective way to increase carbon sequestration in the short term in cotton systems of arid areas.

  4. The Interannual Variability of the Onset of the Maize Growing Season over South Africa and Zimbabwe.

    NASA Astrophysics Data System (ADS)

    Tadross, M. A.; Hewitson, B. C.; Usman, M. T.

    2005-08-01

    Subsistence farmers within southern Africa have identified the onset of the maize growing season as an important seasonal characteristic, advance knowledge of which would aid preparations for the planting of rain-fed maize. Onset over South Africa and Zimbabwe is calculated using rainfall data from the Climate Prediction Center (CPC) Merged Analysis of Precipitation (CMAP) and the Computing Center for Water Research (CCWR). The two datasets present similar estimates of the mean, standard deviation, and trend of onset for the common period (1979-97) over South Africa. During this period, onset has been tending to occur later in the season, in particular over the coastal regions and the Limpopo valley. However, the CCWR data (1950-97) indicate that this is part of long-term (decadal) variability.Characteristic rainfall patterns associated with late and early onset are estimated using a self-organizing map (SOM). Late onset is associated with heavier rainfall over the subcontinent. When onset is early over Zimbabwe, there is an increased frequency of more intense rainfall over northeast Madagascar during the preceding August. Accompanying these intense events is an increased frequency of positive 500-hPa geopotential height anomalies to the southeast of the continent. Similar positive height anomalies are also frequently present during early onset. The study indicates that onset variability is partly forced by synoptic conditions, and the successful use of general circulation models to estimate onset will depend on their simulation of the zonally asymmetric component of the westerly circulation.

  5. A multi-refuge study to evaluate the effectiveness of growing-season and dormant-season burns to control cattail

    USGS Publications Warehouse

    Gleason, Robert A.; Tangen, Brian A.; Laubhan, Murray K.; Lor, Socheata

    2012-01-01

    Proliferation of invasive cattails (for example, Typha x glauca, T. angustifolia) is a concern of wetland managers across the country, and numerous methods have been used to control the spatial extent and density of the plant. To date, however, no single method has proven widely or consistently effective at reducing the long-term growth and spread of these species. We performed a multi-refuge study to evaluate the relative effects of growing-season and dormant-season prescribed burns on cattail production and to gain insight on variables such as soil moisture, groundwater, and biomass that affect the efficacy of burning as a control method. Results indicate total cattail cover recovers to pre-burn levels within 1 year regardless of whether the controlled burn was implemented during the growing season or dormant season. Growing-season burns, however, did result in lower aboveground and belowground cattail biomass 1-year post-burn, whereas no significant change in biomass was detected for dormant-season burns. Study results support the premise that burns implemented during the growing season should have a greater effect on nutrient reserves and cattail re-growth. Results from this and other studies suggest long-term research that incorporates multiple management strategies will be required to evaluate the potential of prescribed burning as a method to control cattail.

  6. Scaling foliar respiration to the stand level throughout the growing season in a Quercus rubra forest.

    PubMed

    Xu, Cheng-Yuan; Griffin, Kevin L

    2008-04-01

    Stand-level, canopy foliar carbon loss (R(can)) was modeled for a virtual Quercus rubra L. monoculture at two sites differing in soil water availability in a northeastern deciduous forest (USA) throughout the 2003 growing season. Previously reported foliar respiratory temperature responses of Q. rubra were used to parameterize a full distributed physiology model that estimates R(can) by integrating the effects of season, site and canopy position, and represents the best estimation of R(can). Model sensitivity to five simplified parameterization scenarios was tested, and a reasonable procedure of simplification was established. Neglecting effects of season, site or canopy position on respiration causes considerable relative error in R(can) estimation. By contrast, assuming a constant E(0) (a temperature response variable of the respiration model), or a constant night temperature (mean nighttime temperature) caused only a small relative error (< 10%) compared with the full model. From June 8 to October 28, 2003, modeled R(can) of the virtual Q. rubra monoculture was, on average, 45.3 mmol CO(2) m(-2) night(-1) on a ground-area basis (or 334 mmol CO(2) kg(-1) night(-1) on a biomass basis) and 101 mmol CO(2) m(-2) night(-1) (or 361 mmol CO(2) kg(-1) night(-1)) at the drier site and the more mesic site, respectively. To model R(can) of Q. rubra (or other Quercus species with similar respiratory properties), variations in the base respiration rate across season, site and canopy position need to be fully accounted for, but E(0) may be assumed constant. Modeling R(can) at the mean nighttime temperature would not strongly affect estimated canopy carbon loss.

  7. Scaling foliar respiration to the stand level throughout the growing season in a Quercus rubra forest.

    PubMed

    Xu, Cheng-Yuan; Griffin, Kevin L

    2008-04-01

    Stand-level, canopy foliar carbon loss (R(can)) was modeled for a virtual Quercus rubra L. monoculture at two sites differing in soil water availability in a northeastern deciduous forest (USA) throughout the 2003 growing season. Previously reported foliar respiratory temperature responses of Q. rubra were used to parameterize a full distributed physiology model that estimates R(can) by integrating the effects of season, site and canopy position, and represents the best estimation of R(can). Model sensitivity to five simplified parameterization scenarios was tested, and a reasonable procedure of simplification was established. Neglecting effects of season, site or canopy position on respiration causes considerable relative error in R(can) estimation. By contrast, assuming a constant E(0) (a temperature response variable of the respiration model), or a constant night temperature (mean nighttime temperature) caused only a small relative error (< 10%) compared with the full model. From June 8 to October 28, 2003, modeled R(can) of the virtual Q. rubra monoculture was, on average, 45.3 mmol CO(2) m(-2) night(-1) on a ground-area basis (or 334 mmol CO(2) kg(-1) night(-1) on a biomass basis) and 101 mmol CO(2) m(-2) night(-1) (or 361 mmol CO(2) kg(-1) night(-1)) at the drier site and the more mesic site, respectively. To model R(can) of Q. rubra (or other Quercus species with similar respiratory properties), variations in the base respiration rate across season, site and canopy position need to be fully accounted for, but E(0) may be assumed constant. Modeling R(can) at the mean nighttime temperature would not strongly affect estimated canopy carbon loss. PMID:18244949

  8. Seasonal trends of whitefly populations in a Mediterranean tomato growing area.

    PubMed

    Nannini, M; Foddi, F; Murgia, G; Pisci, R; Sanna, F; Testa, M

    2009-01-01

    The whiteflies Bemisia tabaci and Trialeurodes vaporariorum and their associated viruses constitute a major threat to tomato crops in the Mediterranean region. Continuous host availability and mild climate are thought to be among the factors contributing to the outbreaks of whitefly-related problems in this area. We carried out a year-long survey to investigate the relative contribution of different plants, agricultural and not, and indoor/outdoor crops as hosts of the two whiteflies and the tomato yellow leaf curl disease (TYLCD) in a multi-crop system typical of tomato growing areas in southern Sardinia (S. Margherita di Pula, Cagliari, Italy). For this purpose, during 2005 we monitored whitefly population trends in different plots of a horticulture farm, evaluated seasonal changes in the infestation density of the two pests on the most represented host species and assessed the incidence of TYLCD on tomato crops and susceptible weeds. Whitefly catches on yellow sticky traps were found to be higher inside et along the external perimeter of greenhouses compared to open field crops or uncultivated areas, thus suggesting significant adult movement between indoor and outdoor patches. In most plots flight activity increased between late spring and late summer, peaking in July. The number of immatures of the two whitefly species showed similar dynamics, but while T. vaporariorum reached the highest densities in greenhouse tomato crops in June, peak levels of 8. tabaci were recorded between July and August in outdoor horticultural crops and weeds. The occurrence of TYLCD was detected all year round on weed hosts, but the highest number of infected plants was observed in June on long cycle tomato crops. The present survey has demonstrated the contribution of non-agricultural plants the maintenance of tomato yellow leaf curl disease in the study site. However, tomato crops established in summer as major reservoirs of TYLCD-associated viruses and presumably played a key

  9. The net exchange of methane with high Arctic landscapes during the summer growing season

    NASA Astrophysics Data System (ADS)

    Emmerton, C. A.; St. Louis, V. L.; Lehnherr, I.; Humphreys, E. R.; Rydz, E.; Kosolofski, H. R.

    2014-06-01

    High Arctic landscapes are essentially vast cold deserts interspersed with streams, ponds and wetlands. These landscapes may be important consumers and sources of the greenhouse gas methane (CH4), though few measurements exist from this region. To quantify the flux of CH4 (FCH4) between the atmosphere and high Arctic landscapes on northern Ellesmere Island, Canada, we made static chamber measurements over five and three growing seasons at a desert and wetland, respectively, and eddy covariance (EC) measurements at a wetland in 2012. Chamber measurements revealed that, during the growing season, desert soils consumed CH4 (-1.37 ± 0.06 mg-CH4 m-2 d-1), whereas the wetland margin emitted CH4 (+0.22 ± 0.14 mg-CH4 m-2 d-1). Desert CH4 consumption rates were positively associated with soil temperature among years, and were similar to temperate locations, likely because of suitable landscape conditions for soil gas diffusion. Wetland FCH4 varied closely with stream discharge entering the wetland and hence extent of soil saturation. Landscape-scale FCH4 measured by EC was +1.27 ± 0.18 mg-CH4 m-2 d-1 and varied with soil temperature and carbon dioxide flux. FCH4 measured using EC was higher than using chambers because EC measurements incorporated a larger, more saturated footprint of the wetland. Using EC FCH4 and quantifying the mass of CH4 entering and exiting the wetland in stream water, we determined that methanogenesis within wetland soils was the dominant source of FCH4. Low FCH4 at the wetland was likely due to a shallow organic soil layer, and thus limited carbon resources for methanogens. Considering the prevalence of dry soils in the high Arctic, our results suggest that these landscapes cannot be overlooked as important consumers of atmospheric CH4.

  10. The net exchange of methane with high Arctic landscapes during the summer growing season

    NASA Astrophysics Data System (ADS)

    St Louis, V. L.; Emmerton, C. A.; Lehnherr, I.; Humphreys, E.; Rydz, E.; Kosolofski, H.

    2014-12-01

    High Arctic landscapes are essentially vast cold deserts interspersed with streams, ponds and wetlands. These landscapes may be important consumers and sources of the greenhouse gas methane (CH4), though few measurements exist from this region. To quantify the flux of CH4 (FCH4) between the atmosphere and high Arctic landscapes on northern Ellesmere Island, Canada, we made static chamber measurements over five and three growing seasons at a desert and wetland, respectively, and eddy covariance (EC) measurements at a wetland in 2012. Chamber measurements revealed that, during the growing season, desert soils consumed CH4 (-1.37±0.06 mg- CH4 m-2 d-1), whereas the wetland margin emitted CH4 (+0.22±0.14 mg- CH4 m-2 d-1). Desert CH4 consumption rates were positively associated with soil temperature among years, and were similar to temperate locations, likely because of suitable landscape conditions for soil gas diffusion. Wetland FCH4 varied closely with stream discharge entering the wetland and hence extent of soil saturation. Landscape-scale FCH4 measured by EC was +1.27±0.18 mg- CH4 m-2 d-1 and varied with soil temperature and carbon dioxide flux. FCH4 measured using EC was higher than using chambers because EC measurements incorporated a larger, more saturated footprint of the wetland. Using EC FCH4 and quantifying the mass of CH4 entering and exiting the wetland in stream water, we determined that methanogenesis within wetland soils was the dominant source of FCH4. Low FCH4 at the wetland was likely due to a shallow organic soil layer, and thus limited carbon resources for methanogens. Considering the prevalence of dry soils in the high Arctic, our results suggest that these landscapes cannot be overlooked as important consumers of atmospheric CH4.

  11. Forest phenology and a warmer climate - Growing season extension in relation to climatic provenance

    SciTech Connect

    Gunderson, Carla A; Edwards, Nelson T; Walker, Ashley V; O'Hara, Keiran H; Campion, Christina M; Hanson, Paul J

    2012-01-01

    Predicting forest responses to warming climates relies on assumptions about niche and temperature sensitivity that remain largely untested. Observational studies have related current and historical temperatures to phenological shifts, but experimental evidence is sparse, particularly for autumn responses. A five-year field experiment exposed four deciduous forest species from contrasting climates (Liquidambar styraciflua, Quercus rubra, Populus grandidentata, and Betula alleghaniensis) to air temperatures 2 and 4 C above ambient controls. Impacts of year-round warming on bud burst (BB), senescence and abscission were evaluated in relation to thermal provenance. Leaves emerged earlier in all species, by an average of 6-9 days at +2 and +4 C. Magnitude of advance varied with species and year, but was larger for the first 2 C increment than the second. The effect of warming increased with early BB, favoring Liquidambar, from the warmest climate, but even BB in northern species advanced, despite temperatures well beyond those of the realized niche. Treatment differences in BB were poorly explained by temperature sums, which increased with treatment. In autumn, chlorophyll was retained an average of 4 and 7 days longer in +2 and +4 C treatments, and abscission delayed by 8 and 13 days. Species differences in autumn responses were marginally significant. Growing seasons in the warmer atmospheres were 6 - 28 days longer, with the least impact in Quercus. Results are compared with a 16-year record of canopy onset and offset in a nearby upland deciduous forest, where BB showed similar responsiveness to spring temperatures (2 - 4 days C-1). Offset dates in the stand tracked August-September temperatures, except when late summer drought caused premature senescence. The common garden-like experimental approach provides evidence that warming alone extends the growing season, at both ends, even if stand-level impacts are complicated by other environmental factors.

  12. Pan-Arctic linkages between snow accumulation and growing-season air temperature, soil moisture and vegetation

    NASA Astrophysics Data System (ADS)

    Luus, K. A.; Gel, Y.; Lin, J. C.; Kelly, R. E. J.; Duguay, C. R.

    2013-11-01

    Arctic field studies have indicated that the air temperature, soil moisture and vegetation at a site influence the quantity of snow accumulated, and that snow accumulation can alter growing-season soil moisture and vegetation. Climate change is predicted to bring about warmer air temperatures, greater snow accumulation and northward movements of the shrub and tree lines. Understanding the responses of northern environments to changes in snow and growing-season land surface characteristics requires: (1) insights into the present-day linkages between snow and growing-season land surface characteristics; and (2) the ability to continue to monitor these associations over time across the vast pan-Arctic. The objective of this study was therefore to examine the pan-Arctic (north of 60° N) linkages between two temporally distinct data products created from AMSR-E satellite passive microwave observations: GlobSnow snow water equivalent (SWE), and NTSG growing-season AMSR-E Land Parameters (air temperature, soil moisture and vegetation transmissivity). Due to the complex and interconnected nature of processes determining snow and growing-season land surface characteristics, these associations were analyzed using the modern nonparametric technique of alternating conditional expectations (ACE), as this approach does not impose a predefined analytic form. Findings indicate that regions with lower vegetation transmissivity (more biomass) at the start and end of the growing season tend to accumulate less snow at the start and end of the snow season, possibly due to interception and sublimation. Warmer air temperatures at the start and end of the growing season were associated with diminished snow accumulation at the start and end of the snow season. High latitude sites with warmer mean annual growing-season temperatures tended to accumulate more snow, probably due to the greater availability of water vapor for snow season precipitation at warmer locations. Regions with drier

  13. Effects of grazing on ecosystem CO₂ exchange in a meadow grassland on the Tibetan Plateau during the growing season.

    PubMed

    Chen, Ji; Shi, Weiyu; Cao, Junji

    2015-02-01

    Effects of human activity on ecosystem carbon fluxes (e.g., net ecosystem exchange (NEE), ecosystem respiration (R(eco)), and gross ecosystem exchange (GEE)) are crucial for projecting future uptake of CO2 in terrestrial ecosystems. However, how ecosystem that carbon fluxes respond to grazing exclusion is still under debate. In this study, a field experiment was conducted to study the effects of grazing exclusion on R(eco), NEE, and GEE with three treatments (free-range grazing (FG) and grazing exclusion for 3 and 5 years (GE3 and GE5, respectively)) in a meadow grassland on the Tibetan Plateau. Our results show that grazing exclusion significantly increased NEE by 47.37 and 15.84%, and R eco by 33.14 and 4.29% under GE3 and GE5 plots, respectively, although carbon sinks occurred in all plots during the growing season, with values of 192.11, 283.12, and 222.54 g C m(-2) for FG, GE3, and GE5, respectively. Interestingly, grazing exclusion increased temperature sensitivity (Q10) of R eco with larger increases at the beginning and end of growing season (i.e., May and October, respectively). Soil temperature and soil moisture were key factors on controlling the diurnal and seasonal variations of R(eco), NEE, and GEE, with soil temperature having a stronger influence. Therefore, the combined effects of grazing and temperature suggest that grazing should be taken into consideration in assessing global warming effects on grassland ecosystem CO2 exchange.

  14. Effects of grazing on ecosystem CO₂ exchange in a meadow grassland on the Tibetan Plateau during the growing season.

    PubMed

    Chen, Ji; Shi, Weiyu; Cao, Junji

    2015-02-01

    Effects of human activity on ecosystem carbon fluxes (e.g., net ecosystem exchange (NEE), ecosystem respiration (R(eco)), and gross ecosystem exchange (GEE)) are crucial for projecting future uptake of CO2 in terrestrial ecosystems. However, how ecosystem that carbon fluxes respond to grazing exclusion is still under debate. In this study, a field experiment was conducted to study the effects of grazing exclusion on R(eco), NEE, and GEE with three treatments (free-range grazing (FG) and grazing exclusion for 3 and 5 years (GE3 and GE5, respectively)) in a meadow grassland on the Tibetan Plateau. Our results show that grazing exclusion significantly increased NEE by 47.37 and 15.84%, and R eco by 33.14 and 4.29% under GE3 and GE5 plots, respectively, although carbon sinks occurred in all plots during the growing season, with values of 192.11, 283.12, and 222.54 g C m(-2) for FG, GE3, and GE5, respectively. Interestingly, grazing exclusion increased temperature sensitivity (Q10) of R eco with larger increases at the beginning and end of growing season (i.e., May and October, respectively). Soil temperature and soil moisture were key factors on controlling the diurnal and seasonal variations of R(eco), NEE, and GEE, with soil temperature having a stronger influence. Therefore, the combined effects of grazing and temperature suggest that grazing should be taken into consideration in assessing global warming effects on grassland ecosystem CO2 exchange. PMID:25355630

  15. Effects of urban green infrastructure (UGI) on local outdoor microclimate during the growing season.

    PubMed

    Wang, Yafei; Bakker, Frank; de Groot, Rudolf; Wörtche, Heinrich; Leemans, Rik

    2015-12-01

    This study analyzed how the variations of plant area index (PAI) and weather conditions alter the influence of urban green infrastructure (UGI) on microclimate. To observe how diverse UGIs affect the ambient microclimate through the seasons, microclimatic data were measured during the growing season at five sites in a local urban area in The Netherlands. Site A was located in an open space; sites B, C, and D were covered by different types and configurations of green infrastructure (grove, a single deciduous tree, and street trees, respectively); and site E was adjacent to buildings to study the effects of their façades on microclimate. Hemispherical photography and globe thermometers were used to quantify PAI and thermal comfort at both shaded and unshaded locations. The results showed that groves with high tree density (site B) have the strongest effect on microclimate conditions. Monthly variations in the differences of mean radiant temperature (∆Tmrt) between shaded and unshaded areas followed the same pattern as the PAI. Linear regression showed a significant positive correlation between PAI and ∆Tmrt. The difference of daily average air temperature (∆T a ) between shaded and unshaded areas was also positively correlated to PAI, but with a slope coefficient below the measurement accuracy (±0.5 °C). This study showed that weather conditions can significantly impact the effectiveness of UGI in regulating microclimate. The results of this study can support the development of appropriate UGI measures to enhance thermal comfort in urban areas.

  16. Growing degree-days for the `Niagara Rosada' grapevine pruned in different seasons

    NASA Astrophysics Data System (ADS)

    Scarpare, Fábio Vale; Scarpare Filho, João Alexio; Rodrigues, Alessandro; Reichardt, Klaus; Angelocci, Luiz Roberto

    2012-09-01

    Plant growth and development are proportional to biological time, or the thermal time of the species, which can be defined as the integral of the temperature over time between the lower and upper temperature developmental thresholds. The objective of this study was to investigate the efficiency of the growing degree-day (GDD) approach for vines of the `Niagara Rosada' cultivar pruned in winter and summer seasons, and physiological phases (mobilisation and reserve accumulation) in a humid subtropical region. The experiment was carried out on 13-year-old plants in Piracicaba, São Paulo State-Brazil, evaluating 24 production cycles, 12 from the winter pruning, and 12 from the summer pruning. The statistical design was comprised of randomised blocks, using the pruning dates as treatment: 20 July, 4 August, 19 August, and 3 September (winter); 1 February, 15 February, 2 March, and 16 March (summer). Comparison of the mean values of GDD among pruning dates was evaluated by the Tukey test, and comparison between pruning seasons was made by the F test for orthogonal contrasts, both at the 5% probability level. The results showed good agreement between the values of GDD required to complete the cycle from the winter pruning until harvest when compared with other studies performed with the same cultivar grown in the Southern and Southeastern regions of Brazil. However, there was a consistent statistical difference between GDD computed for winter and summer pruning, which allowed us to conclude that this bio-meteorological index is not sufficient to distinguish vines pruned in different seasons and physiological phases applied in humid subtropical climates.

  17. Growing degree-days for the 'Niagara Rosada' grapevine pruned in different seasons.

    PubMed

    Scarpare, Fábio Vale; Scarpare Filho, João Alexio; Rodrigues, Alessandro; Reichardt, Klaus; Angelocci, Luiz Roberto

    2012-09-01

    Plant growth and development are proportional to biological time, or the thermal time of the species, which can be defined as the integral of the temperature over time between the lower and upper temperature developmental thresholds. The objective of this study was to investigate the efficiency of the growing degree-day (GDD) approach for vines of the 'Niagara Rosada' cultivar pruned in winter and summer seasons, and physiological phases (mobilisation and reserve accumulation) in a humid subtropical region. The experiment was carried out on 13-year-old plants in Piracicaba, São Paulo State-Brazil, evaluating 24 production cycles, 12 from the winter pruning, and 12 from the summer pruning. The statistical design was comprised of randomised blocks, using the pruning dates as treatment: 20 July, 4 August, 19 August, and 3 September (winter); 1 February, 15 February, 2 March, and 16 March (summer). Comparison of the mean values of GDD among pruning dates was evaluated by the Tukey test, and comparison between pruning seasons was made by the F test for orthogonal contrasts, both at the 5% probability level. The results showed good agreement between the values of GDD required to complete the cycle from the winter pruning until harvest when compared with other studies performed with the same cultivar grown in the Southern and Southeastern regions of Brazil. However, there was a consistent statistical difference between GDD computed for winter and summer pruning, which allowed us to conclude that this bio-meteorological index is not sufficient to distinguish vines pruned in different seasons and physiological phases applied in humid subtropical climates.

  18. Growing degree-days for the 'Niagara Rosada' grapevine pruned in different seasons.

    PubMed

    Scarpare, Fábio Vale; Scarpare Filho, João Alexio; Rodrigues, Alessandro; Reichardt, Klaus; Angelocci, Luiz Roberto

    2012-09-01

    Plant growth and development are proportional to biological time, or the thermal time of the species, which can be defined as the integral of the temperature over time between the lower and upper temperature developmental thresholds. The objective of this study was to investigate the efficiency of the growing degree-day (GDD) approach for vines of the 'Niagara Rosada' cultivar pruned in winter and summer seasons, and physiological phases (mobilisation and reserve accumulation) in a humid subtropical region. The experiment was carried out on 13-year-old plants in Piracicaba, São Paulo State-Brazil, evaluating 24 production cycles, 12 from the winter pruning, and 12 from the summer pruning. The statistical design was comprised of randomised blocks, using the pruning dates as treatment: 20 July, 4 August, 19 August, and 3 September (winter); 1 February, 15 February, 2 March, and 16 March (summer). Comparison of the mean values of GDD among pruning dates was evaluated by the Tukey test, and comparison between pruning seasons was made by the F test for orthogonal contrasts, both at the 5% probability level. The results showed good agreement between the values of GDD required to complete the cycle from the winter pruning until harvest when compared with other studies performed with the same cultivar grown in the Southern and Southeastern regions of Brazil. However, there was a consistent statistical difference between GDD computed for winter and summer pruning, which allowed us to conclude that this bio-meteorological index is not sufficient to distinguish vines pruned in different seasons and physiological phases applied in humid subtropical climates. PMID:21866380

  19. Controls for multi-scale temporal variation in ecosystem methane exchange during the growing season of a permanently inundated fen

    NASA Astrophysics Data System (ADS)

    Koebsch, Franziska; Jurasinski, Gerald; Koch, Marian; Hofmann, Joachim; Glatzel, Stephan

    2014-05-01

    Temperature and phenology trigger seasonal variation of CH4 emissions in many ecosystems. However, ecosystem CH4 exchange varies also considerably on smaller temporal scales such as days or weeks. Indeed, we are aware of many processes that control CH4 emissions on the local soil-plant-atmosphere continuum, but their interaction on ecosystem level is not well understood yet. We used a quasi-continuous Eddy Covariance CH4 flux time series and wavelet analysis to describe the temporal variation of ecosystem CH4 exchange within the growing season of a permanently inundated temperate fen. Moreover, we assigned time scale-specific controls and investigated whether their impact changes during the course of the growing season. Water/soil temperature correlated with ecosystem CH4 exchange at time scales of 6-11 and 22 days which exceeds the time scales that are typically associated with the passage of weather fronts. The low response time might be due to the high heat capacity of the water column. On a daily scale, shear-induced turbulence (presented by friction velocity) and plant activity (presented by canopy photosynthesis) caused a diurnal variation of ecosystem CH4 exchange with peak time around noon. However, this pattern was apparent only at the beginning of the growing season (April/May). In the following, convective mixing of the water column (presented by the water temperature gradient) gradually gained importance and caused high night-time CH4 emissions, thereby levelling off the diurnal CH4 emission pattern. Our study highlights the need for multi-scale approaches that consider the non-stationarity of the underlying processes to adequately describe the complexity of ecosystem CH4 exchange. Moreover, we show that CH4 release processes such as convective mixing of the water column which has been mainly known from aquatic ecosystems until recently (Godwin et al. 2013), might be also of importance in shallowly flooded terrestrial ecosystems. Citation: Godwin CM, Mc

  20. Longer growing seasons shift grassland vegetation towards more-productive species

    NASA Astrophysics Data System (ADS)

    Fridley, Jason D.; Lynn, Josh S.; Grime, J. P.; Askew, A. P.

    2016-09-01

    Despite advances in plant functional ecology that provide a framework for predicting the responses of vegetation to environmental change, links between plant functional strategies and elevated temperatures are poorly understood. Here, we analyse the response of a species-rich grassland in northern England to two decades of temperature and rainfall manipulations in the context of the functional attributes of 21 coexisting species that represent a large array of resource-use strategies. Three principal traits, including body size (canopy height), tissue investment (leaf construction cost), and seed size, varied independently across species and reflect tradeoffs associated with competitiveness, stress tolerance, and colonization ability. Unlike past studies, our results reveal a strong association between functional traits and temperature regime; species favoured by extended growing seasons have taller canopies and faster assimilation rates, which has come at the expense of those species of high tissue investment. This trait-warming association was three times higher in deep soils, suggesting species shifts have been strongly mediated by competition. In contrast, vegetation shifts from rainfall manipulations have been associated only with tissue investment. Functional shifts towards faster growing species in response to warming may be responsible for a marginal increase in productivity in a system that was assumed to be nutrient-limited.

  1. Response of phyllosphere bacterial communities to elevated CO2 during rice growing season.

    PubMed

    Ren, Gaidi; Zhang, Huayong; Lin, Xiangui; Zhu, Jianguo; Jia, Zhongjun

    2014-11-01

    The phyllosphere, the aerial parts of terrestrial plants, represents the largest biological interface on Earth. This habitat is colonized by diverse microorganisms that affect plant health and growth. However, the community structure of these phyllosphere microorganisms and their responses to environmental changes, such as rising atmospheric CO2, are poorly understood. Using a massive parallel pyrosequencing technique, we investigated the feedback of a phyllosphere bacterial community in rice to elevated CO2 (eCO2) at the tillering, filling, and maturity stages under nitrogen fertilization with low (LN) and high application rates (HN). The results revealed 9,406 distinct operational taxonomic units that could be classified into 8 phyla, 13 classes, 26 orders, 59 families, and 120 genera. The family Enterobacteriaceae within Gammaproteobacteria was the most dominant phylotype during the rice growing season, accounting for 61.0-97.2 % of the total microbial communities. A statistical analysis indicated that the shift in structure and composition of phyllosphere bacterial communities was largely dependent on the rice growing stage. eCO2 showed a distinct effect on the structure of bacterial communities at different growth stages, and the most evident response of the community structure to eCO2 was observed at the filling stage. eCO2 significantly increased the relative abundance of the most dominant phylotype (Enterobacteriaceae) from 88.6 % at aCO2 (ambient CO2) to 97.2 % at eCO2 under LN fertilization at the filling stage, while it significantly decreased the total relative abundance of other phylotypes from 7.48 to 1.35 %. Similarly, higher value for the relative abundance of the most dominant family (Enterobacteriaceae) and lower value for the total relative abundance of other families were observed under eCO2 condition at other growth stages and under different N fertilizations, but the difference was not statistically significant. No consistent response pattern

  2. Impact of mulches and growing season on indicator bacteria survival during lettuce cultivation.

    PubMed

    Xu, Aixia; Buchanan, Robert L; Micallef, Shirley A

    2016-05-01

    In fresh produce production, the use of mulches as ground cover to retain moisture and control weeds is a common agricultural practice, but the influence that various mulches have on enteric pathogen survival and dispersal is unknown. The goal of this study was to assess the impact of different mulching methods on the survival of soil and epiphytic fecal indicator bacteria on organically grown lettuce during different growing seasons. Organically managed lettuce, cultivated with various ground covers--polyethylene plastic, corn-based biodegradable plastic, paper and straw mulch--and bare ground as a no-mulch control, was overhead inoculated with manure-contaminated water containing known levels of generic Escherichia coli and Enterococcus spp. Leaves and soil samples were collected at intervals over a two week period on days 0, 1, 3, 5, 7, 10 and 14, and quantitatively assessed for E. coli, fecal coliforms and Enterococcus spp. Data were analyzed using mixed models with repeated measures and an exponential decline with asymptote survival model. Indicator bacterial concentrations in the lettuce phyllosphere decreased over time under all treatments, with more rapid E. coli declines in the fall than in the spring (p<0.01). Persistence of E. coli in spring was correlated with higher maximum and minimum temperatures in this season, and more regular rainfall. The survival model gave very good fits for the progression of E. coli concentrations in the phyllosphere over time (R(2)=0.88 ± 0.12). In the spring season, decline rates of E. coli counts were faster (2013 p=0.18; 2014 p<0.005) for the bare ground-cultivated lettuce compared to mulches. In fall 2014, the E. coli decline rate on paper mulch-grown lettuce was higher (p<0.005). Bacteria fluctuated more, and persisted longer, in soil compared to lettuce phyllosphere, and mulch type was a factor for fecal coliform levels (p<0.05), with higher counts retrieved under plastic mulches in all trials, and higher enterococci

  3. Impact of mulches and growing season on indicator bacteria survival during lettuce cultivation.

    PubMed

    Xu, Aixia; Buchanan, Robert L; Micallef, Shirley A

    2016-05-01

    In fresh produce production, the use of mulches as ground cover to retain moisture and control weeds is a common agricultural practice, but the influence that various mulches have on enteric pathogen survival and dispersal is unknown. The goal of this study was to assess the impact of different mulching methods on the survival of soil and epiphytic fecal indicator bacteria on organically grown lettuce during different growing seasons. Organically managed lettuce, cultivated with various ground covers--polyethylene plastic, corn-based biodegradable plastic, paper and straw mulch--and bare ground as a no-mulch control, was overhead inoculated with manure-contaminated water containing known levels of generic Escherichia coli and Enterococcus spp. Leaves and soil samples were collected at intervals over a two week period on days 0, 1, 3, 5, 7, 10 and 14, and quantitatively assessed for E. coli, fecal coliforms and Enterococcus spp. Data were analyzed using mixed models with repeated measures and an exponential decline with asymptote survival model. Indicator bacterial concentrations in the lettuce phyllosphere decreased over time under all treatments, with more rapid E. coli declines in the fall than in the spring (p<0.01). Persistence of E. coli in spring was correlated with higher maximum and minimum temperatures in this season, and more regular rainfall. The survival model gave very good fits for the progression of E. coli concentrations in the phyllosphere over time (R(2)=0.88 ± 0.12). In the spring season, decline rates of E. coli counts were faster (2013 p=0.18; 2014 p<0.005) for the bare ground-cultivated lettuce compared to mulches. In fall 2014, the E. coli decline rate on paper mulch-grown lettuce was higher (p<0.005). Bacteria fluctuated more, and persisted longer, in soil compared to lettuce phyllosphere, and mulch type was a factor for fecal coliform levels (p<0.05), with higher counts retrieved under plastic mulches in all trials, and higher enterococci

  4. Seasonal variation in chemistry, but not morphology, in roots of Quercus robur growing in different soil types.

    PubMed

    Zadworny, Marcin; McCormack, M Luke; Rawlik, Katarzyna; Jagodziński, Andrzej M

    2015-06-01

    Patterns of root traits among different root orders and their variation across seasons are of considerable importance for soil resource acquisition and partitioning in forest ecosystems. We evaluated whether morphological, anatomical and biochemical traits varied among root orders of Quercus robur (L.) sampled across spring, summer and fall seasons and growing in two different soil types with contrasting site fertility. We found no consistent differences in root diameter and specific root length in relation to soil type or growing season. There was, however, a strong seasonal variation in patterns of nitrogen (N) concentration among root orders. During spring and summer, N concentration was highest in the most distal, absorptive portion of the root system. At the end of the growing season, we observed a sharp decline in the N concentration of these lower-order, absorptive roots and an increase in N concentration of the higher-order, transport roots. The specific mechanisms driving the seasonally changing N concentration remain unclear but are likely related to different functions of lower-order roots for absorption and higher-order roots for structure and storage. Future work should identify how common the observed seasonal changes in N concentration are across species and determine what specific environmental cues plants or roots use to trigger shifts in resource allocation within the root branching hierarchy.

  5. The Seasons Explained by Refutational Modeling Activities

    ERIC Educational Resources Information Center

    Frede, Valerie

    2008-01-01

    This article describes the principles and investigation of a small-group laboratory activity based on refutational modeling to teach the concept of seasons to preservice elementary teachers. The results show that these teachers improved significantly when they had to refute their initial misconceptions practically. (Contains 8 figures and 1 table.)

  6. Effects of urban green infrastructure (UGI) on local outdoor microclimate during the growing season.

    PubMed

    Wang, Yafei; Bakker, Frank; de Groot, Rudolf; Wörtche, Heinrich; Leemans, Rik

    2015-12-01

    This study analyzed how the variations of plant area index (PAI) and weather conditions alter the influence of urban green infrastructure (UGI) on microclimate. To observe how diverse UGIs affect the ambient microclimate through the seasons, microclimatic data were measured during the growing season at five sites in a local urban area in The Netherlands. Site A was located in an open space; sites B, C, and D were covered by different types and configurations of green infrastructure (grove, a single deciduous tree, and street trees, respectively); and site E was adjacent to buildings to study the effects of their façades on microclimate. Hemispherical photography and globe thermometers were used to quantify PAI and thermal comfort at both shaded and unshaded locations. The results showed that groves with high tree density (site B) have the strongest effect on microclimate conditions. Monthly variations in the differences of mean radiant temperature (∆Tmrt) between shaded and unshaded areas followed the same pattern as the PAI. Linear regression showed a significant positive correlation between PAI and ∆Tmrt. The difference of daily average air temperature (∆T a ) between shaded and unshaded areas was also positively correlated to PAI, but with a slope coefficient below the measurement accuracy (±0.5 °C). This study showed that weather conditions can significantly impact the effectiveness of UGI in regulating microclimate. The results of this study can support the development of appropriate UGI measures to enhance thermal comfort in urban areas. PMID:26547322

  7. The effect of a permafrost disturbance on growing-season carbon-dioxide fluxes in a high Arctic tundra ecosystem

    NASA Astrophysics Data System (ADS)

    Cassidy, Alison E.; Christen, Andreas; Henry, Gregory H. R.

    2016-04-01

    Soil carbon stored in high-latitude permafrost landscapes is threatened by warming and could contribute significant amounts of carbon to the atmosphere and hydrosphere as permafrost thaws. Thermokarst and permafrost disturbances, especially active layer detachments and retrogressive thaw slumps, are present across the Fosheim Peninsula, Ellesmere Island, Canada. To determine the effects of retrogressive thaw slumps on net ecosystem exchange (NEE) of CO2 in high Arctic tundra, we used two eddy covariance (EC) tower systems to simultaneously and continuously measure CO2 fluxes from a disturbed site and the surrounding undisturbed tundra. During the 32-day measurement period in the 2014 growing season, the undisturbed tundra was a small net sink (NEE = -0.1 g C m-2 d-1); however, the disturbed terrain of the retrogressive thaw slump was a net source (NEE = +0.4 g C m-2 d-1). Over the measurement period, the undisturbed tundra sequestered 3.8 g C m-2, while the disturbed tundra released 12.5 g C m-2. Before full leaf-out in early July, the undisturbed tundra was a small source of CO2 but shifted to a sink for the remainder of the sampling season (July), whereas the disturbed tundra remained a source of CO2 throughout the season. A static chamber system was also used to measure daytime fluxes in the footprints of the two towers, in both disturbed and undisturbed tundra, and fluxes were partitioned into ecosystem respiration (Re) and gross primary production (GPP). Average GPP and Re found in disturbed tundra were smaller (+0.40 µmol m-2 s-1 and +0.55 µmol m-2 s-1, respectively) than those found in undisturbed tundra (+1.19 µmol m-2 s-1 and +1.04 µmol m-2 s-1, respectively). Our measurements indicated clearly that the permafrost disturbance changed the high Arctic tundra system from a sink to a source for CO2 during the majority of the growing season (late June and July).

  8. The effect of a permafrost disturbance on growing-season carbon-dioxide fluxes in a high Arctic tundra ecosystem

    NASA Astrophysics Data System (ADS)

    Cassidy, A. E.; Christen, A.; Henry, G. H. R.

    2015-12-01

    Soil carbon stored in high-latitude permafrost landscapes is threatened by warming, and could contribute significant amounts of carbon to the atmosphere and hydrosphere as permafrost thaws. Permafrost disturbances, especially active layer detachments and retrogressive thaw slumps, have increased in frequency and magnitude across the Fosheim Peninsula, Ellesmere Island, Canada. To determine the effects of retrogressive thaw slumps on net ecosystem exchange (NEE) of CO2 in high Arctic tundra, we used two eddy covariance (EC) tower systems to simultaneously and continuously measure CO2 fluxes from a disturbed site and the surrounding undisturbed tundra. During the 32-day measurement period in the 2014 growing season the undisturbed tundra was a small net sink (NEE = -0.12 g C m-2 d-1); however, the disturbed terrain of the retrogressive thaw slump was a net source (NEE = +0.39 g C m-2 d-1). Over the measurement period, the undisturbed tundra sequestered 3.84 g C m-2, while the disturbed tundra released 12.48 g C m-2. Before full leaf out in early July, the undisturbed tundra was a small source of CO2, but shifted to a sink for the remainder of the sampling season (July), whereas the disturbed tundra remained a source of CO2 throughout the season. A static chamber system was also used to measure fluxes in the footprints of the two towers, in both disturbed and undisturbed tundra, and fluxes were partitioned into ecosystem respiration (Re) and gross primary production (GPP). Average GPP and Re found in disturbed tundra were smaller (+0.41 μmol m-2 s-1 and +0.50 μmol m-2 s-1, respectively) than those found in undisturbed tundra (+1.21 μmol m-2 s-1 and +1.00 μmol m-2 s-1, respectively). Our measurements indicated clearly that the permafrost disturbance changed the high Arctic tundra system from a sink to a source for CO2 during the growing season.

  9. Rainfall-derived growing season characteristics for agricultural impact assessments in South Africa

    NASA Astrophysics Data System (ADS)

    Ambrosino, Chiara; Chandler, Richard E.; Todd, Martin C.

    2014-02-01

    Precipitation variability imposes significant pressure in areas where agricultural practice is dominated by smallholder farmers who are dependent on subsistence farming. Advances in the understanding of this variability, in both time and space, have an important role to play in increasing the resilience of agricultural systems. The need is particularly pressing in regions of the world such as the African continent, which is already affected by multiple stresses including poverty and economic and political instability. In this paper, we explore the use of generalised linear models (GLMs) for this purpose, via a case study from north-east South Africa. A GLM is used to link the local rainfall variability to large-scale climate drivers identified from previous subcontinental-scale analyses, and the ability of the resulting model to simulate precipitation features that are relevant in agricultural applications is evaluated. We focus in particular on a set of growing season indices, proposed for the investigation of intraseasonal characteristics relevant for maize production in the region. Seven indices were computed from spatially averaged daily rainfall series from nine stations in the study area. As a first attempt to use GLMs for this type of application, the results are encouraging and suggest that the models are able to reproduce a range of agriculture-relevant indices. However, further research into spatial correlation structure is recommended to improve the multisite generation of the rainfall-derived characteristics.

  10. Seasonality on the rainfall partitioning of a fast-growing tree plantation under Mediterranean conditions

    NASA Astrophysics Data System (ADS)

    molina, antonio; llorens, pilar; biel, carme

    2014-05-01

    Studies on rainfall interception in fast-growing tree plantations are less numerous than those in natural forests. Trees in these plantations are regularly distributed, and the canopy cover is clumped but changes quickly, resulting on high variability in the volume and composition of water that reach the soil. In addition, irrigation supply is normally required in semiarid areas to get optimal wood production; consequently, knowing rainfall interception and its yearly evolution is crucial to manage the irrigation scheme properly. This work studies the rainfall partitioning seasonality in a cherry tree (Prunus avium) plantation orientated to timber production under Mediterranean conditions. The monitoring design started on March 2012 and consists of a set of 58 throughfall tipping buckets randomly distributed (based on a 1x1 m2 grid) in a plot of 128 m2 with 8 trees. Stemflow is measured in all the trees with 2 tipping buckets and 6 accumulative collectors. Canopy cover is regularly measured throughout the study period, in leaf and leafless periods, by mean of sky-orientated photographs taken 50 cm above the center of each tipping bucket. Others tree biometrics are also measured such as diameter and leaf area index. Meteorological conditions are measured at 2 m above the forest cover. This work presents the first analyses describing the rainfall partitioning and its dependency on canopy cover, distance to tree and meteorological conditions. The modified Gash' model for rainfall interception in dispersed vegetation is also preliminary evaluated.

  11. Response of the Morus bombycis growing season to temperature and its latitudinal pattern in Japan.

    PubMed

    Doi, Hideyuki

    2012-09-01

    Changes in leaf phenology lengthen the growing season length (GSL, the days between leaf budburst and leaf fall) under the global warming. GSL and the leaf phenology response to climate change is one of the most important predictors of climate change effect on plants. Empirical evidence of climatic effects on GSL remains scarce, especially at a regional scale and the latitudinal pattern. This study analyzed the datasets of leaf budburst and fall phenology in Morus bombycis (Urticales), which were observed by the agency of the Japan Meteorological Agency (JMA) from 1953 to 2005 over a wide range of latitudes in Japan (31 to 44° N). In the present study, single regression slopes of leaf phenological timing and air temperature across Japan were calculated and their spatial patterns using general linear models were tested. The results showed that the GSL extension was caused mainly by a delay in leaf fall phenology. Relationships between latitude and leaf phenological and GSL responses against air temperature were significantly negative. The response of leaf phenology and GSL to air temperature at lower latitudes was larger than that at higher latitudes. The findings indicate that GSL extension should be considered with regards to latitude and climate change.

  12. Variation in peak growing season net ecosystem production across the Canadian Arctic.

    PubMed

    Lafleur, Peter M; Humphreys, Elyn R; St Louis, Vincent L; Myklebust, May C; Papakyriakou, Tim; Poissant, Laurier; Barker, Joel D; Pilote, Martin; Swystun, Kyle A

    2012-08-01

    Tundra ecosystems store vast amounts of soil organic carbon, which may be sensitive to climatic change. Net ecosystem production, NEP, is the net exchange of carbon dioxide (CO(2)) between landscapes and the atmosphere, and represents the balance between CO(2) uptake by photosynthesis and release by decomposition and autotrophic respiration. Here we examine CO(2) exchange across seven sites in the Canadian low and high Arctic during the peak growing season (July) in summer 2008. All sites were net sinks for atmospheric CO(2) (NEP ranged from 5 to 67 g C m(-2)), with low Arctic sites being substantially larger CO(2) sinks. The spatial difference in NEP between low and high Arctic sites was determined more by CO(2) uptake via gross ecosystem production than by CO(2) release via ecosystem respiration. Maximum gross ecosystem production at the low Arctic sites (average 8.6 μmol m(-2) s(-1)) was about 4 times larger than for high Arctic sites (average 2.4 μmol m(-2) s(-1)). NEP decreased with increasing temperature at all low Arctic sites, driven largely by the ecosystem respiration response. No consistent temperature response was found for the high Arctic sites. The results of this study clearly indicate there are large differences in tundra CO(2) exchange between high and low Arctic environments and this difference should be a central consideration in studies of Arctic carbon balance and climate change.

  13. Simulated water fluxes during the growing season in semiarid grassland ecosystems under severe drought conditions

    NASA Astrophysics Data System (ADS)

    Zhang, Na; Liu, Chengyu

    2014-05-01

    To help improve understanding of how changes in climate and land cover affect water fluxes, water budgets, and the structure and function of regional grassland ecosystems, the Grassland Landscape Productivity Model (GLPM) was used to simulate spatiotemporal variation in primary water fluxes. The study area was a semiarid region in Inner Mongolia, China, in 2002, when severe drought was experienced. For Stipa grandis steppe, Leymus chinensis steppe, shrubland, and croplands, the modeled total, daily and monthly averaged, and maximum evapotranspiration during the growing season and the modeled water deficits were similar to those measured in Inner Mongolia under similar precipitation conditions. The modeled temporal variations in daily evaporation rate, transpiration rate, and evapotranspiration rate for the typical steppes also agreed reasonably well with measured trends. The results demonstrate that water fluxes varied in response to spatiotemporal variations in environmental factors and associated changes in the phenological and physiological characteristics of plants. It was also found that transpiration and evapotranspiration (rather than precipitation) were the primary factors controlling differences in water deficit among land cover types. The results also demonstrate that specific phenomena occur under severe drought conditions; these phenomena are considerably different to those occurring under normal or well-watered conditions. The findings of the present study will be useful for evaluating day-scale water fluxes and their relationships with climate change, hydrology, land cover, and vegetation dynamics.

  14. Soil nitrogen transformations under elevated atmospheric CO2 and O3 during the soybean growing season

    PubMed Central

    Pereira, Engil Isadora Pujol; Chung, Haegeun; Scow, Kate; Sadowsky, Michael J.; van Kessel, Chris; Six, Johan

    2012-01-01

    We investigated the influence of elevated CO2 and O3 on soil N cycling within the soybean growing season and across soil environments (i.e., rhizosphere and bulk soil) at the Soybean Free Air Concentration Enrichment (SoyFACE) experiment in Illinois, USA. Elevated O3 decreased soil mineral N likely through a reduction in plant material input and increased denitrification, which was evidenced by the greater abundance of the denitrifier gene nosZ. Elevated CO2 did not alter the parameters evaluated and both elevated CO2 and O3 showed no interactive effects on nitrifier and denitrifier abundance, nor on total and mineral N concentrations. These results indicate that elevated CO2 may have limited effects on N transformations in soybean agroecosystems. However, elevated O3 can lead to a decrease in soil N availability in both bulk and rhizosphere soils, and this likely also affects ecosystem productivity by reducing the mineralization rates of plant-derived residues. PMID:21115216

  15. Temporal evolution of the macropore network and saturated hydraulic conductivity in an arable, clayey topsoil during one growing season

    NASA Astrophysics Data System (ADS)

    Sandin, Maria; Köstel, Johannes; Jarvis, Nicholas; Larsbo, Mats

    2015-04-01

    Soil macropore networks and thus hydraulic properties at and close to saturation vary considerably with time, as a result of the dynamic nature of a diverse range of interacting soil structure-forming and degrading factors such as tillage and traffic events, faunal and plant root activity, swell/shrink arising from wetting and drying cycles, freeze-thaw etc. These properties are nevertheless treated as constants in most hydrological modelling studies. This is mostly justified by a lack of understanding of the processes driving these changes. Temporal variations of saturated and near-saturated hydraulic conductivity have been studied in the field (e.g. by tension disc infiltrometer), but these measurements only indirectly reflect the characteristics of the macropore network. In this study, we used non-destructive X-ray tomography to investigate the temporal changes in the macropore network characteristics occurring in the harrowed layer of a conventionally-tilled agricultural field over one growing season. Undisturbed soil cores (60-70 mm height, 68 mm diameter) were sampled on five different occasions. Changes in the geometric and topological properties of the X-ray imaged macropore system (voxel resolution = 120 µm) were compared with variations in saturated hydraulic conductivity measured on the same samples. Image analysis showed that total porosity, specific surface area, average pore diameter and the connectivity of the pore system in the uppermost 60-70 mm of ploughed and harrowed soil decreased from the first sampling occasion shortly after seedbed preparation and sowing until the middle of the growing season after which it slightly increased again. Separate analysis of the total porosity of the top 5 mm showed a marked decrease between the first two sampling occasions, followed by a gradual increase. Despite these structural changes in the macropore system, saturated hydraulic conductivity was only weakly correlated with macropore network characteristics.

  16. Non-growing season soil CO2 efflux patterns in five land-use types in northern China

    NASA Astrophysics Data System (ADS)

    Pan, Zhanlei; Johnson, Douglas A.; Wei, Zhijun; Ma, Lei; Rong, Yuping

    2016-11-01

    Heavy grazing and unsuitable farming practices have led to grassland degradation in northern China. This study examined soil CO2 efflux (Fc) from five land-use types during the non-growing season on the southeastern edge of the Mongolian Plateau in China. The land-use types included three native vegetation steppes subjected to differing stocking rates [ungrazed (UG), moderately grazed (MG) and heavily grazed (HG)], a fertilized annual cropland (CL) and a perennial pasture (PP) used for haying and winter grazing. Values of Fc were measured at 3-day to 2-week intervals during the non-growing season in two contrasting hydrological years (2012-13 and 2013-14) using closed chambers. The Fc during 1 Oct. 2013 to 30 April 2014 averaged 475 mg C m-2 for all sites compared to a significantly (P < 0.05) lower Fc (102 mg C m-2) during 1 Oct. 2012 to 30 April 2013. The seasonal Fc patterns followed the same trend during the two non-growing seasons with greater Fc observed in the autumn and spring freeze-thaw periods compared to the winter permanently frozen period, which accounted for 4.8% of accumulated total non-growing season Fc. The heavily grazed site showed less soil CO2 efflux compared to UG, MG, PP and CL land-use types due to a larger reduction in gross primary productivity (GPP) compared to ecosystem respiration. Grazing reduced Fc by 23% for MG and 32% for HG compared to UG. Soil CO2 efflux from the PP land-use type, which was grazed during the non-growing season, was 23% greater than that from the UG and CL land-use types. Air temperature during the non-growing season was the main factor controlling soil CO2 efflux (R2 = 0.40, P < 0.001), although soil water content also played a role. Precipitation received during the growing season had a large legacy effect on Fc. Annual weather variation overshadowed the influence of land-use types on Fc.

  17. Long-term experimentally deepened snow decreases growing-season respiration in a low- and high-arctic tundra ecosystem

    NASA Astrophysics Data System (ADS)

    Semenchuk, Philipp R.; Christiansen, Casper T.; Grogan, Paul; Elberling, Bo; Cooper, Elisabeth J.

    2016-05-01

    Tundra soils store large amounts of carbon (C) that could be released through enhanced ecosystem respiration (ER) as the arctic warms. Over time, this may change the quantity and quality of available soil C pools, which in-turn may feedback and regulate ER responses to climate warming. Therefore, short-term increases in ER rates due to experimental warming may not be sustained over longer periods, as observed in other studies. One important aspect, which is often overlooked, is how climatic changes affecting ER in one season may carry-over and determine ER in following seasons. Using snow fences, we increased snow depth and thereby winter soil temperatures in a high-arctic site in Svalbard (78°N) and a low-arctic site in the Northwest Territories, Canada (64°N), for 5 and 9 years, respectively. Deepened snow enhanced winter ER while having negligible effect on growing-season soil temperatures and soil moisture. Growing-season ER at the high-arctic site was not affected by the snow treatment after 2 years. However, surprisingly, the deepened snow treatments significantly reduced growing-season ER rates after 5 years at the high-arctic site and after 8-9 years at the low-arctic site. We speculate that the reduction in ER rates, that became apparent only after several years of experimental manipulation, may, at least in part, be due to prolonged depletion of labile C substrate as a result of warmer soils over multiple cold seasons. Long-term changes in winter climate may therefore significantly influence annual net C balance not just because of increased wintertime C loss but also because of "legacy" effects on ER rates during the following growing seasons.

  18. 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.

  19. Plant phenological responses to a long-term experimental extension of growing season and soil warming in the tussock tundra of Alaska.

    PubMed

    Khorsand Rosa, Roxaneh; Oberbauer, Steven F; Starr, Gregory; Parker La Puma, Inga; Pop, Eric; Ahlquist, Lorraine; Baldwin, Tracey

    2015-12-01

    Climate warming is strongly altering the timing of season initiation and season length in the Arctic. Phenological activities are among the most sensitive plant responses to climate change and have important effects at all levels within the ecosystem. We tested the effects of two experimental treatments, extended growing season via snow removal and extended growing season combined with soil warming, on plant phenology in tussock tundra in Alaska from 1995 through 2003. We specifically monitored the responses of eight species, representing four growth forms: (i) graminoids (Carex bigellowii and Eriophorum vaginatum); (ii) evergreen shrubs (Ledum palustre, Cassiope tetragona, and Vaccinium vitis-idaea); (iii) deciduous shrubs (Betula nana and Salix pulchra); and (iv) forbs (Polygonum bistorta). Our study answered three questions: (i) Do experimental treatments affect the timing of leaf bud break, flowering, and leaf senescence? (ii) Are responses to treatments species-specific and growth form-specific? and (iii) Which environmental factors best predict timing of phenophases? Treatment significantly affected the timing of all three phenophases, although the two experimental treatments did not differ from each other. While phenological events began earlier in the experimental plots relative to the controls, duration of phenophases did not increase. The evergreen shrub, Cassiope tetragona, did not respond to either experimental treatment. While the other species did respond to experimental treatments, the total active period for these species did not increase relative to the control. Air temperature was consistently the best predictor of phenology. Our results imply that some evergreen shrubs (i.e., C. tetragona) will not capitalize on earlier favorable growing conditions, putting them at a competitive disadvantage relative to phenotypically plastic deciduous shrubs. Our findings also suggest that an early onset of the growing season as a result of decreased snow cover

  20. Plant phenological responses to a long-term experimental extension of growing season and soil warming in the tussock tundra of Alaska.

    PubMed

    Khorsand Rosa, Roxaneh; Oberbauer, Steven F; Starr, Gregory; Parker La Puma, Inga; Pop, Eric; Ahlquist, Lorraine; Baldwin, Tracey

    2015-12-01

    Climate warming is strongly altering the timing of season initiation and season length in the Arctic. Phenological activities are among the most sensitive plant responses to climate change and have important effects at all levels within the ecosystem. We tested the effects of two experimental treatments, extended growing season via snow removal and extended growing season combined with soil warming, on plant phenology in tussock tundra in Alaska from 1995 through 2003. We specifically monitored the responses of eight species, representing four growth forms: (i) graminoids (Carex bigellowii and Eriophorum vaginatum); (ii) evergreen shrubs (Ledum palustre, Cassiope tetragona, and Vaccinium vitis-idaea); (iii) deciduous shrubs (Betula nana and Salix pulchra); and (iv) forbs (Polygonum bistorta). Our study answered three questions: (i) Do experimental treatments affect the timing of leaf bud break, flowering, and leaf senescence? (ii) Are responses to treatments species-specific and growth form-specific? and (iii) Which environmental factors best predict timing of phenophases? Treatment significantly affected the timing of all three phenophases, although the two experimental treatments did not differ from each other. While phenological events began earlier in the experimental plots relative to the controls, duration of phenophases did not increase. The evergreen shrub, Cassiope tetragona, did not respond to either experimental treatment. While the other species did respond to experimental treatments, the total active period for these species did not increase relative to the control. Air temperature was consistently the best predictor of phenology. Our results imply that some evergreen shrubs (i.e., C. tetragona) will not capitalize on earlier favorable growing conditions, putting them at a competitive disadvantage relative to phenotypically plastic deciduous shrubs. Our findings also suggest that an early onset of the growing season as a result of decreased snow cover

  1. Seasonal and cumulative loblolly pine development under two stand density and fertility levels through four growing seasons. Forest Service research paper

    SciTech Connect

    Haywood, J.D.

    1994-06-01

    A loblolly pine (Pinus taeda) plantation was subjected to two cultural treatments to examine seasonal cumulative pine development in the 9th through 12th growing seasons: (1) pine stocking was either reduced by thinning to 303 trees per acre at a 12- by 12-ft spacing or the plots were left uncut with an original density of 1,210 trees per acre at a 6- by 6-ft spacing, and (2) either no fertilizer was applied or diammonium phosphate was broadcast at 134 lb of phosphorus and 120 lb of nitrogen per acre. Competing vegetation was controlled on all plots. Thinning resulted in less spring height growth in the 9th and 10th growing seasons that not cutting, but thinning increased diameter growth each year. Beginning in the 10th growing season, fertilization increased height, diameter, and basal area per acre growth, with the effect of fertilization on diameter growth being most pronounced on the thinned plots. Therefore, fertilization of thinned plots was more beneficial than thinning alone, and thinning alone resulted in less height and basal area per acre growth than the other treatment combinations for the 4-year period.

  2. Non-growing season soil CO2 efflux patterns in five land-use types in northern China

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Overgrazing and unsuitable farming practices have led to grassland degradation in northern China. This studhy examined soil CO2 efflux (Fc) from five land-use types during the non-growing season on the southeastern edge of the Mongolian Plateau in China. The land-use types included three native v...

  3. Earlier growing seasons and changes in migration timing influence carbon uptake and plant production in Arctic coastal wetlands

    NASA Astrophysics Data System (ADS)

    Leffler, A. J.; Beard, K. H.; Kelsey, K.; Choi, R. T.; Welker, J. M.

    2015-12-01

    The wetlands of the Yukon-Kuskokwim Delta in western Alaska are important breeding areas for geese and are experiencing rapid climate change, specifically earlier onset of the growing season. Consequently, geese arrive 'later' in the growing season than in the past, potentially setting up a phenological mismatch with consequences for their nutrition, plant growth, and C and N processes in the ecosystem. We examined the interactive effects between the start of the growing season and Black Brant arrival time on these processes in a manipulative experiment. Advancing the growing season had a modest influence on CO2 exchange and plant growth. An early growing season shifted the rate of net ecosystem exchange (NEE) by 1-1.5 µmol m-2 s-1 toward a carbon (C) source. This change was driven by an increase in the rate of ecosystem respiration (ER). The advanced growing season nearly doubled the rate of leaf elongation in the early summer and this difference persisted as taller vegetation later in the year; belowground biomass was not affected. Timing of grazing had greater influence on CO2 exchange and plant growth. Grazing early in the season shifted the system to a carbon source by ca. 2 μmol m-2 s-1 while delaying grazing enhanced the carbon sink by 1 μmol m-2 s-1. Here, the influence was not through ER, but through reducing and enhancing standing leaf area, respectively. Early grazing also reduced season-long root production by over 50% while delayed grazing enhanced root production by 30%. Although delaying grazing enhanced C uptake and promoted plant growth in this ecosystem, leaf tissue in delayed-grazing plots had C:N of 16.7 compared to 14.2 in the typical-grazing plots, potentially reducing the digestibility of goose forage and slowing rates of decomposition. Biotic forcing in arctic tundra can thus be major drivers of ecosystem function and need to be considered as tundra system respond to changing conditions.

  4. n-Alkane biosynthetic hydrogen isotope fractionation is not constant throughout the growing season in the riparian tree Salix viminalis

    NASA Astrophysics Data System (ADS)

    Newberry, Sarah L.; Kahmen, Ansgar; Dennis, Paul; Grant, Alastair

    2015-09-01

    Compound-specific δ2H values of leaf wax n-alkanes have emerged as a potentially powerful paleohydrological proxy. Research suggests terrestrial plant n-alkane δ2H values are strongly correlated with meteoric water δ2H values, and may provide information on temperature, relative humidity, evaporation, and precipitation. This is based upon several assumptions, including that biosynthetic fractionation of n-alkanes during synthesis is constant within a single species. Here we present a multi-isotope study of the n-alkanes of riparian Salix viminalis growing in Norwich, UK. We measured n-alkane δ2H, leaf water δ2H, xylem water δ2H, and bulk foliar δ13C and evaluated the variability of n-alkane δ2H values and net biosynthetic fractionation (εlw-wax) over a whole growing season. S. viminalis n-alkane δ2H values decreased by 40‰ between the start of the growing season in April and the time when they stabilized in July. Variation in leaf and xylem water δ2H did not explain this variability. εlw-wax varied from -116‰ during leaf expansion in April to -156‰ during the stable phase. This suggests that differential biosynthetic fractionation was responsible for the strong seasonal trends in S. viminalis n-alkane δ2H values. We suggest that variability in εlw-wax is driven by seasonal differences in the carbohydrate source and thus the NADPH used in n-alkane biosynthesis, with stored carbohydrates utilized during spring and recent occurring growing season assimilates used later in the season. This is further supported by bulk foliar δ13C values, which are 13C-enriched during the period of leaf flush, relative to the end of the growing season. Our results challenge the assumption that biosynthetic fractionation is constant for a given species, and suggest that 2H-enriched stored assimilates are an important source for n-alkane biosynthesis early in the growing season. These findings have implications for the interpretation of sedimentary n-alkanes and call

  5. The net exchange of methane with high Arctic landscapes during the summer growing season

    NASA Astrophysics Data System (ADS)

    Emmerton, C. A.; St. Louis, V. L.; Lehnherr, I.; Humphreys, E. R.; Rydz, E.; Kosolofski, H. R.

    2014-01-01

    High Arctic landscapes are essentially vast cold deserts interspersed with streams, ponds and wetlands. These landscapes may be important consumers and sources of the greenhouse gas methane (CH4), though few measurements exist from this region. To quantify the flux of CH4 (FCH4) between the atmosphere and desert and wetland landscapes on northern Ellesmere Island, Canada, we made static chamber measurements at both locations over five growing seasons and eddy covariance (EC) measurements at the wetland in 2012. Chamber measurements revealed that desert soils consumed CH4 (-1.37 ± 0.10 mg-CH4 m-2 d-1) whereas the wetland emitted CH4 (+0.22 ± 0.19 mg-CH4 m-2 d-1). Desert CH4 consumption rates were positively correlated with soil temperature among years, and were similar to temperate locations, likely because of suitable landscape conditions for soil gas diffusion. Wetland FCH4 varied closely with stream discharge entering the wetland and hence extent of soil saturation. Landscape-scale FCH4 measured by EC was +1.27± 0.18 mg-CH4 m-2 d-1 and varied with soil temperature and carbon dioxide flux. FCH4 measured using EC was higher than using chambers because EC incorporated a arger, more saturated footprint of the wetland. Using EC FCH4 and quantifying the mass of CH4 entering and exiting the wetland in stream water, we determined that methanogenisis within wetland soils was the dominant source of FCH4. Low FCH4 at the wetland was likely due to a shallow organic soil layer, and thus limited carbon resources for methanogens. Considering the prevalence of dry soils in the high Arctic, our results suggest that these landscapes cannot be overlooked as important consumers of atmospheric CH4.

  6. Effects of application of corn straw on soil microbial community structure during the maize growing season.

    PubMed

    Lu, Ping; Lin, Yin-Hua; Yang, Zhong-Qi; Xu, Yan-Peng; Tan, Fei; Jia, Xu-Dong; Wang, Miao; Xu, De-Rong; Wang, Xi-Zhuo

    2015-01-01

    This study investigated the influence of corn straw application on soil microbial communities and the relationship between such communities and soil properties in black soil. The crop used in this study was maize (Zea mays L.). The five treatments consisted of applying a gradient (50, 100, 150, and 200%) of shattered corn straw residue to the soil. Soil samples were taken from May through September during the 2012 maize growing season. The microbial community structure was determined using phospholipid fatty acid (PLFA) analysis. Our results revealed that the application of corn straw influenced the soil properties and increased the soil organic carbon and total nitrogen. Applying corn straw to fields also influenced the variation in soil microbial biomass and community composition, which is consistent with the variations found in soil total nitrogen (TN) and soil respiration (SR). However, the soil carbon-to-nitrogen ratio had no effect on soil microbial communities. The abundance of PLFAs, TN, and SR was higher in C1.5 than those in other treatments, suggesting that the soil properties and soil microbial community composition were affected positively by the application of corn straw to black soil. A Principal Component Analysis indicated that soil microbial communities were different in the straw decomposition processes. Moreover, the soil microbial communities from C1.5 were significantly different from those of CK (p < 0.05). We also found a high ratio of fungal-to-bacterial PLFAs in black soil and significant variations in the ratio of monounsaturated-to-branched fatty acids with different straw treatments that correlated with SR (p < 0.05). These results indicated that the application of corn straw positively influences soil properties and soil microbial communities and that these properties affect these communities. The individual PLFA signatures were sensitive indicators that reflected the changes in the soil environment condition.

  7. Sensitivity study of reference crop evapotranspiration during growing season in the West Liao River basin, China

    NASA Astrophysics Data System (ADS)

    Gao, Zhendong; He, Junshi; Dong, Kebao; Bian, Xiaodong; Li, Xiang

    2016-05-01

    We have analyzed the trends of reference crop evapotranspiration (ET0) through the Penman-Monteith model and climate factors in the West Liao River basin using the Mann-Kendall test after removing the effect of significant lag-1 serial correlation from the time series of the data by trend-free pre-whitening. The changing characteristics of the sensitivity coefficients and the spatial distribution during growing season are investigated, and the correlation between the sensitivity coefficients with elevation and the key climate factors by relative contribution and stepwise regression methods are evaluated. A significant overall increase in air temperature, and a significant decrease in wind speed, solar radiation, sunshine duration, relative humidity, and a slight decrease in ET0 are observed. Sensitivity analysis shows that ET0 is most sensitive to solar radiation, followed by relative humidity. In contrast, ET0 is least sensitive to the average air temperature. The sensitivity coefficients for the maximum and minimum air temperature and relative humidity have a significant negative correlation with elevation, while the coefficients for other variables are not strongly correlated with elevation. The spatial distribution of the sensitivity coefficients for wind speed and solar radiation is opposite, i.e., in regions where the sensitivity coefficients for wind speed are high; the sensitivity coefficients for solar radiation are low and vice versa. The sensitivity for relative humidity and average air temperature is region specific in the plain area. However, ET0 is most sensitive to the climate change in regions of high elevation. Wind speed is the most dominant contributor followed by solar radiation. Average air temperature contributes the least. The stepwise regression analysis indicates that wind speed is the foremost dominant variable influencing ET0. Relative contribution and stepwise regression analysis can be used to determine the main variables affecting ET0

  8. Climate-dependent costs of reproduction: survival and fecundity costs decline with length of the growing season and summer temperature.

    PubMed

    Sletvold, Nina; Ågren, Jon

    2015-04-01

    Costs of reproduction are expected to vary with environmental conditions thus influencing selection on life-history traits. Yet, the effects of habitat conditions and climate on trade-offs among fitness components remain poorly understood. For 2-5 years, we quantified costs of experimentally increased reproduction in two populations (coastal long-season vs. inland short-season) of two long-lived orchids that differ in natural reproductive effort (RE; 30 vs. 75% fruit set). In both species, survival costs were found only at the short-season site, whereas growth and fecundity costs were evident at both sites, and both survival and fecundity costs declined with increasing growing season length and/or summer temperature. The results suggest that the expression of costs of reproduction depend on the local climate, and that climate warming could result in selection favouring increased RE in both study species.

  9. Likely changes in growing season indices under a climate change scenario for crop production in South Africa

    NASA Astrophysics Data System (ADS)

    Ambrosino, C.; Chandler, R. E.; Todd, M. C.

    2011-12-01

    Agriculture is still the major source of income and livelihood for most of South Africa's population, and cereals and grains are among the country's most important crops. In particular, the largest locally produced field crop and the most important source of carbohydrates in South Africa is maize (Zea mays L.). As well as extensive monoculture, maize production also dominates the smallholder farming system in areas such as the Limpopo District in north-east South Africa. It is therefore critical to understand the year-to-year changes in the planting season and rainfall characteristics in order to introduce management decision and mitigation measures in the agricultural sector (e.g. planting of drought-resistant crops or the choice between long and short-season cultivars). Indeed, one of the strategies that may be easily introduced by farmers is shifting the crop planting dates to adjust to changes in the rainfall regimes. The study presented here aims to characterise the inter-annual growing season variability through the use of 7 indices derived from daily precipitation, considered the most critical factor in rain-fed agriculture, having an impact on maize production. A statistical model is developed to generate daily rainfall sequences for the study area driven by large scale climate controls. An independent validation period is chosen to evaluate the performance of the statistical model in the rainfall generation process. Onset, length and cessation of the growing season, as well as indices representing the length of the mean and maximum dry spell during the season are derived from the area average daily simulated precipitation values. The fraction of rainy days and total precipitation during the growing season are also calculated. Finally, the projected change of the growing season indices between two investigated periods in the 20th and 21st centuries is investigated under a climate change scenario (a1b; e.g.: Fig.1). The outputs of this study may be used to

  10. Growing Together with the Treetures. Activity Guide. Series 1.

    ERIC Educational Resources Information Center

    Schnell, Bobbi; Blau, Judith H.; Hinrichs, Jennifer Judd

    This activity guide is designed to be used with the Growing Together program. Tree-related activities are correlated to the Benchmarks for Scientific Literacy, the recommended standards for mathematics, science, and technology suggested by the American Association for the Advancement of Science (AAAS). The Treature Educational Program is dedicated…

  11. Growing season temperature and precipitation variability and extremes in the U.S. Corn Belt from 1981 to 2012

    NASA Astrophysics Data System (ADS)

    Dai, S.; Shulski, M.

    2013-12-01

    Climate warming and changes in rainfall patterns and increases in extreme events are resulting in higher risks of crop failures. A greater sense of urgency has been induced to understand the impacts of past climate on crop production in the U.S. As one of the most predominant sources of feed grains, corn is also the main source of U.S. ethanol. In the U.S. Corn Belt, region-scale evaluation on temperature and precipitation variability and extremes during the growing season is not well-documented yet. This study is part of the USDA-funded project 'Useful to Usable: Transforming climate variability and change information for cereal crop producers'. The overall goal of our work is to study the characteristics of average growing season conditions and changes in growing season temperature- and precipitation-based indices that are closely correlated with corn grain yield in the U.S. Corn Belt. The research area is the twelve major Corn Belt states, including IL, IN, IA, KS, MI, MN, MO, NE, OH, SD, ND, and WI. Climate data during 1981-2010 from 132 meteorological stations (elevation ranges from 122 m to 1,202 m) are used in this study, including daily minimum, maximum, and mean temperature, and daily precipitation. From 1981 to 2012, beginning date (BD), ending date (ED), and growing season length (GSL) in the climatological corn growing season are studied. Especially, during the agronomic corn growing season, from Apr to Oct, temperature- and precipitation-based indices are analyzed. The temperature-based indices include: number of days with daily mean temperature below 10°C, number of days with daily mean temperature above 30°C, the sum of growing degree days (GDD) between 10°C to 30°C (GDD10,30, growth range for corn), the sum of growing degree days above 30°C (GDD30+, exposure to harmful warming for corn), the sum of growing degree days between 0°C and 44°C (GDD0,44, survival range limits for corn), the sum of growing degree days between 5°C and 35°C (GDD5

  12. Growth, allocation and tissue chemistry of Picea abies seedlings affected by nutrient supply during the second growing season.

    PubMed

    Kaakinen, Seija; Jolkkonen, Annika; Iivonen, Sari; Vapaavuori, Elina

    2004-06-01

    One-year-old Norway spruce (Picea abies (L.) Karst.) seedlings were grown hydroponically in a growth chamber to investigate the effects of low and high nutrient availability (LN; 0.25 mM N and HN; 2.50 mM N) on growth, biomass allocation and chemical composition of needles, stem and roots during the second growing season. Climatic conditions in the growth chamber simulated the mean growing season from May to early October in Flakaliden, northern Sweden. In the latter half of the growing season, biomass allocation changed in response to nutrient availability: increased root growth and decreased shoot growth led to higher root/shoot ratios in LN seedlings than in HN seedlings. At high nutrient availability, total biomass, especially stem biomass, increased, as did total nonstructural carbohydrate and nitrogen contents per seedling. Responses of stem chemistry to nutrient addition differed from those of adult trees of the same provenance. In HN seedlings, concentrations of alpha-cellulose, hemicellulose and lignin decreased in the secondary xylem. Our results illustrate the significance of retranslocation of stored nutrients to support new growth early in the season when root growth and nutrient uptake are still low. We conclude that nutrient availability alters allocation patterns, thereby influencing the success of 2-year-old Norway spruce seedlings at forest planting sites. PMID:15059771

  13. Calculating High Resolution CWSI Maps for Entire Growing Season of a Cultivated Barley Field with UAV-Collected Surface Temperatures.

    NASA Astrophysics Data System (ADS)

    Hoffmann, H.; Jensen, R.; Nieto Solana, H.; Friborg, T.; Thomsen, A.

    2015-12-01

    With agriculture as the largest consumer of freshwater and an overall increasing pressure on water resources, developing more efficient irrigation systems is important. Combining the crop water stress index (CWSI) with unmanned aerial vehicles (UAVs) enables detection of which specific areas within a cultivated field that requires irrigation to ensure healthy growing plants. In this study remotely sensed, high resolution surface temperatures are collected with a thermal camera onboard an UAV. Temperatures are used to calculate spatially distributed, high resolution CWSI maps over a barley field during growing seasons 2014 and 2015. In early stages of the barley growing season, surface temperatures are an ensemble of both soil and canopy temperatures. Canopy temperatures are extracted using leaf area index and the two source energy balance modelling scheme. This approach enables CWSI calculations for homogeneous and evenly distributed crops (such as barley) during early as well as late stages of a growing season. CWSI maps are calculated using both an empirical and an analytical approach and are compared and validated against modelled canopy conductance and transpiration rates.

  14. Temporal variability of atmospheric particulate matter and chemical composition during a growing season at an agricultural site in northeastern China.

    PubMed

    Chen, Weiwei; Tong, Daniel; Zhang, Shichun; Dan, Mo; Zhang, Xuelei; Zhao, Hongmei

    2015-12-01

    This study presents the observations of PM10 and PM2.5 concentrations at an agricultural site from April to October 2012 in Dehui city, China. Ambient air was sampled by filter-based samplers and online PM monitors. The filter samples were analyzed to determine the abundance of ionic/inorganic elements, organic carbon (OC) and elemental carbon (EC). The daily PM10 concentrations varied significantly over the monitoring period, with an average of 168±63 (in the range of 52-277)μg/m(3) during the land preparation/planting period (26 April-15 June), 85±65 (36-228)μg/m(3) during the growing season (16 June-25 September), and 207±88 (103-310)μg/m(3) during the harvest period (26 September-31 October). PM2.5 accounted for 44%, 56% and 66% of atmospheric PM10 during these periods, respectively. The PM10 diurnal variation showed a distinct peak from 16:00 to 21:00 (LST) during the growing and harvesting seasons, while a gradual increase throughout the daytime until 17:00 was observed during tilling season. Mineral dust elements (Al, Ca, Fe, and Mg) dominated the PM10 chemical composition during the tilling season; OC, NO3(-), SO4(2-) and NH4(+) during the growing season; and carbonaceous species (i.e., OC and EC) during the harvesting season. Our results indicate that the soil particles emitted by farm tillage and organic matter released from straw burning are the two most significant sources of PM10 emissions contributing to the recurring high pollution events in this region. Therefore, development of agricultural PM inventories from soil tillage and straw burning is prioritized to support air quality modeling.

  15. Temperature drives inter-annual variability of growing season CO2 and CH4 fluxes of Siberian lowland tundra

    NASA Astrophysics Data System (ADS)

    Kutzbach, Lars; Wille, Christian; Runkle, Benjamin; Schreiber, Peter; Sachs, Torsten; Langer, Moritz; Boike, Julia; Pfeiffer, Eva-Maria

    2015-04-01

    Due to the logistic and technical difficulties associated with experimental work in high latitudes, long-term measurements of CO2 and CH4 fluxes from arctic ecosystems are still rare, and published trace gas balances often rely on measurements from one or few growing seasons. The inter-annual variability of environmental conditions such as temperature, precipitation, snow cover, and timing of snow melt can be high in the Arctic, especially for regions which are influenced by both continental and maritime climates, such as the Siberian arctic lowlands. For these ecosystems, we must also expect a great inter-annual variability in the balance of trace gases. Multi-annual data sets are needed to investigate this variability and its drivers. Here we present multi-annual late summer CO2 and CH4 flux data from the Lena River Delta in the Siberian Arctic (72° N, 126° E). The study site Samoylov Island is characterized by polygonal lowland tundra, a vegetation dominated by mosses and sedges, a soil complex of Glacic, Turbic and Histic Cryosols, and an active layer depth of on average 0.5 m. Seasonal flux measurements were carried out with the eddy covariance technique during the 13-year period 2002 - 2014. Within this period, CO2 flux data overlaps during 37 days (20 July - 25 August) for 12 years, and CH4 flux data overlaps during 25 days (28 July - 21 August) for 9 years. Cumulative net ecosystem CO2 exchange (NEE) during the late summer overlap period is fairly consistent for 9 out of 12 years with a CO2 uptake of 1.9 ± 0.1 mol m-2. Three years show a clearly smaller uptake of

  16. [Effects of cropping systems on nitrous oxide emissions from paddy soils during the rice-growing season].

    PubMed

    Xiong, Zhengqin; Xing, Guangxi; Shi, Shulian; Du, Lijuan

    2003-10-01

    Cropping systems influence nitrous oxide (N2O) emissions from agricultural soils. Effects of 3 rice-based cropping systems on N2O emissions from paddy soils in pot experiment were investigated with closed chambers in triplicate. The results demonstrated that the seasonal N2O emission rate of the rice pot under rice-wheat cropping system was obviously higher than that of the early rice pot under double rice-wheat system, being 4.21 and 2.17 kg.hm-2, respectively. No distinct difference was observed between the seasonal average fluxes, which were 116.9 and 117.6 micrograms.m-2.h-1 respectively. Both of above mentioned seasonal average fluxes were greatly higher than that of the late rice pot under early rice-late rice-wheat cropping system and of rice pot under rice-flooding fallow system, being 67.0 and 42.1 micrograms.m-2.h-1 respectively. More than 91% of the seasonal emission was focused on the first half growing period both in the rice season in rice-wheat system and in the early rice season in double rice-wheat system in which the previous cropping was upland wheat. 91% of the seasonal emission was focused on the water drainage period including the mid-season aeration and final drainage in the late rice season in double rice-wheat system in which the previous cropping was lowland rice. The results implied that cropping system and water status of previous cropping impacted N2O emission from paddy soil. PMID:14986383

  17. Consumption of eelgrass (Zostera marina L.) by the isopod idotea chelipes (pallas) in lake Grevelingen, after the growing season

    NASA Astrophysics Data System (ADS)

    Groenendijk, A. M.

    Autumn and winter consumption of eelgrass ( Zostera marina L.) by the isopod Idotea chelipes (Pallas) was calculated by means of estimating biomass of both Idotea and eelgrass in the field, and consumption experiments in the laboratory. During the research period, September 1978 to March 1979, Idotea was found to be most abundant (in terms of biomass) invertebrate species in the eelgrass beds of Lake Grevelingen. Calculations show that Idotea can only play a minor role in the breakdown of eelgrass after the growing season: only between 2.9 and 5.8% (maximally) of the standing crop of eelgrass at the 3 permanent plots was consumed by this invertebrate. The fast decline of the standing eelgrass crop after the growing season in mainly due to transport of large leaf fragments (>10 cm) from the eelgrass beds by wind and wave action.

  18. Positive effects of night warming on physiology of coniferous trees in late growing season: Leaf and root

    NASA Astrophysics Data System (ADS)

    Tang, Bo; Yin, Chunying; Wang, Yujie; Sun, Yuyu; Liu, Qing

    2016-05-01

    Previous studies about the effects of experimental warming on tree species have focused primarily on response of morphology and physiology in leaf and biomass allocation in the growing season, and a few studies considered the importance of roots. Based on the available evidence, it is unclear whether photosynthesis rate is enhanced by night warming in late autumn an issue that deserves further investigation. Thus, we exposed two coniferous species, Picea asperata and Abies faxoniana, to night warming continued throughout the year to investigate morphological and physiological responses of roots and leaves in the autumn. The results showed that night warming caused significant increases in net influxes of NH4+ and NO3- in P. asperata seedlings corresponding well with net H+ efflux and net influx of O2. Meanwhile, night warming had a positive effect on foliar gas exchange such as net photosynthesis rate, apparent quantum efficiency, dark respiration rate and maximum quantum efficiency of PS II, and nitrate reductase activity of roots. Additionally, root morphology such as total roots length, surface area, specific root area and specific root length was also stimulated by night warming. In contrast, night warming decreased concentrations of non-structural carbohydrate in leaves and roots of both species in autumn. The present study demonstrates that night warming would enhance late autumn leaf photosynthetic rate, and increase N uptake capacity of roots.

  19. Transcriptome profiling in fast versus slow-growing rainbow trout across seasonal gradients

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Background: Circannual rhythms in vertebrates can influence a wide variety of physiological processes. Some notable examples include annual reproductive cycles and for poikilotherms, seasonal changes modulating growth. Increasing water temperature elevates growth rates in fishes, but increases i...

  20. Growing with EASE: Eating, Activity, and Self-Esteem

    ERIC Educational Resources Information Center

    Huettig, Carol; Rich, Shannon; Engelbrecht, Jo Ann; Sanborn, Charlotte; Essery, Eve; DiMarco, Nancy; Velez, Luisa; Levy, Luba

    2006-01-01

    A diverse group of professionals associated with Texas Woman's University's Institute for Women's Health, working collaboratively with school administrators, teachers, family support teams, and family members, developed Growing with EASE: Eating, Activity, and Self-Esteem, a nutrition program for young children and their families. In tracking the…

  1. Growing Season Length as a Key Factor of Cumulative Net Ecosystem Exchange Over the Pine Forest Ecosystems in Europe

    NASA Astrophysics Data System (ADS)

    Danielewska, Alina; Urbaniak, Marek; Olejnik, Janusz

    2015-04-01

    The Scots pine is one of the most important species in European and Asian forests. Due to a widespread occurrence of pine forests, their significance in the energy and mass exchange between the Earth surface and the atmosphere is also important, particularly in the context of climate change and greenhouse gases balance. The aim of this work is to present the relationship between the average annual net ecosystem productivity and growing season length, latitude and air temperature (tay) over Europe. Therefore, CO2 flux measurement data from eight European pine dominated forests were used. The observations suggest that there is a correlation between the intensity of CO2 uptake or emission by a forest stand and the above mentioned parameters. Based on the obtained results, all of the selected pine forest stands were CO2 sinks, except a site in northern Finland. The carbon dioxide uptake increased proportionally with the increase of growing season length (9.212 g C m-2 y-1 per day of growing season, R2 = 0.53, p = 0.0399). This dependency showed stronger correlation and higher statistical significance than both relationships between annual net ecosystem productivity and air temperature (R2 = 0.39, p = 0.096) and annual net ecosystem productivity and latitude (R2 = 0.47, p = 0.058). The CO2 emission surpassed assimilation in winter, early spring and late autumn. Moreover, the appearance of late, cold spring and early winter, reduced annual net ecosystem productivity. Therefore, the growing season length can be considered as one of the main factor affecting the annual carbon budget of pine forests.

  2. Seasonality in Children's Pedometer-Measured Physical Activity Levels

    ERIC Educational Resources Information Center

    Beighle, Aaron; Alderman, Brandon; Morgan, Charles F.; Le Masurier, Guy

    2008-01-01

    Seasonality appears to have an impact on children's physical activity levels, but equivocal findings demand more study in this area. With the increased use of pedometers in both research and practice, collecting descriptive data in various seasons to examine the impact of seasonality on pedometer-measured physical activity among children is…

  3. Anhydrous Ammonia Injection Depth Does Not Affect Nitrous Oxide Emissions in a Silt Loam over Two Growing Seasons.

    PubMed

    Maharjan, Bijesh; Venterea, Rodney T

    2014-09-01

    Anhydrous ammonia (AA) is a major fertilizer source in North America that can promote greater emissions of nitrous oxide (NO) than other nitrogen (N) fertilizers. Previous studies found that injection of AA at a shallow depth (0.1 m) decreased NO in a rainfed clay loam but increased NO in an irrigated loamy sand compared with the standard injection depth of 0.2 m. The objective of this study was to evaluate the effects of AA injection depth in a silt loam soil used for corn ( L.) production and managed under two contrasting tillage regimes over two consecutive growing seasons (2010 and 2011) in Minnesota. In contrast with previous studies, AA placement depth did not affect NO emissions in either tillage system or in either growing season. Tillage by itself affected NO emissions only in the drier of two seasons, during which NO emissions under no tillage (NT) exceeded those under conventional tillage (CT) by 55%. Soil moisture content under NT was also greater than under CT only in the drier of the two seasons. Effects of AA placement depth and long-term tillage regime on NO emissions exhibit intersite as well as interannual variation, which should be considered when developing NO mitigation strategies. Further study is needed to identify specific soil, climate, or other factors that mediate the contrasting responses to management practices across sites.

  4. Changes in growing season duration and productivity of northern vegetation inferred from long-term remote sensing data

    NASA Astrophysics Data System (ADS)

    Park, Taejin; Ganguly, Sangram; Tømmervik, Hans; Euskirchen, Eugénie S.; Høgda, Kjell-Arild; Rune Karlsen, Stein; Brovkin, Victor; Nemani, Ramakrishna R.; Myneni, Ranga B.

    2016-08-01

    Monitoring and understanding climate-induced changes in the boreal and arctic vegetation is critical to aid in prognosticating their future. We used a 33 year (1982-2014) long record of satellite observations to robustly assess changes in metrics of growing season (onset: SOS, end: EOS and length: LOS) and seasonal total gross primary productivity. Particular attention was paid to evaluating the accuracy of these metrics by comparing them to multiple independent direct and indirect growing season and productivity measures. These comparisons reveal that the derived metrics capture the spatio-temporal variations and trends with acceptable significance level (generally p < 0.05). We find that LOS has lengthened by 2.60 d dec-1 (p < 0.05) due to an earlier onset of SOS (-1.61 d dec-1, p < 0.05) and a delayed EOS (0.67 d dec-1, p < 0.1) at the circumpolar scale over the past three decades. Relatively greater rates of changes in growing season were observed in Eurasia (EA) and in boreal regions than in North America (NA) and the arctic regions. However, this tendency of earlier SOS and delayed EOS was prominent only during the earlier part of the data record (1982-1999). During the later part (2000-2014), this tendency was reversed, i.e. delayed SOS and earlier EOS. As for seasonal total productivity, we find that 42.0% of northern vegetation shows a statistically significant (p < 0.1) greening trend over the last three decades. This greening translates to a 20.9% gain in productivity since 1982. In contrast, only 2.5% of northern vegetation shows browning, or a 1.2% loss of productivity. These trends in productivity were continuous through the period of record, unlike changes in growing season metrics. Similarly, we find relatively greater increasing rates of productivity in EA and in arctic regions than in NA and the boreal regions. These results highlight spatially and temporally varying vegetation dynamics and are reflective of biome-specific responses of northern

  5. Temperature and geographic attribution of change in the Taraxacum mongolicum growing season from 1990 to 2009 in eastern China's temperate zone.

    PubMed

    Chen, Xiaoqiu; Tian, Youhua; Xu, Lin

    2015-10-01

    Using leaf unfolding and leaf coloration data of a widely distributed herbaceous species, Taraxacum mongolicum, we detected linear trend and temperature response of the growing season at 52 stations from 1990 to 2009. Across the research region, the mean growing season beginning date marginal significantly advanced at a rate of -2.1 days per decade, while the mean growing season end date was significantly delayed at a rate of 3.1 days per decade. The mean growing season length was significantly prolonged at a rate of 5.1 days per decade. Over the 52 stations, linear trends of the beginning date correlate negatively with linear trends of spring temperature, whereas linear trends of the end date and length correlate positively with linear trends of autumn temperature and annual mean temperature. Moreover, the growing season linear trends are also closely related to the growing season responses to temperature and geographic coordinates plus elevation. Regarding growing season responses to temperature, a 1 °C increase in regional mean spring temperature results in an advancement of 2.1 days in regional mean growing season beginning date, and a 1 °C increase in regional mean autumn temperature causes a delay of 2.3 days in regional mean growing season end date. A 1 °C increase in regional annual mean temperature induces an extension of 8.7 days in regional mean growing season length. Over the 52 stations, response of the beginning date to spring temperature depends mainly on local annual mean temperature and geographic coordinates plus elevation. Namely, a 1 °C increase in spring temperature induces a larger advancement of the beginning date at warmer locations with lower latitudes and further west longitudes than at colder locations with higher latitudes and further east longitudes, while a 1 °C increase in spring temperature causes a larger advancement of the beginning date at higher than at lower elevations. PMID:25627826

  6. Temperature and geographic attribution of change in the Taraxacum mongolicum growing season from 1990 to 2009 in eastern China's temperate zone.

    PubMed

    Chen, Xiaoqiu; Tian, Youhua; Xu, Lin

    2015-10-01

    Using leaf unfolding and leaf coloration data of a widely distributed herbaceous species, Taraxacum mongolicum, we detected linear trend and temperature response of the growing season at 52 stations from 1990 to 2009. Across the research region, the mean growing season beginning date marginal significantly advanced at a rate of -2.1 days per decade, while the mean growing season end date was significantly delayed at a rate of 3.1 days per decade. The mean growing season length was significantly prolonged at a rate of 5.1 days per decade. Over the 52 stations, linear trends of the beginning date correlate negatively with linear trends of spring temperature, whereas linear trends of the end date and length correlate positively with linear trends of autumn temperature and annual mean temperature. Moreover, the growing season linear trends are also closely related to the growing season responses to temperature and geographic coordinates plus elevation. Regarding growing season responses to temperature, a 1 °C increase in regional mean spring temperature results in an advancement of 2.1 days in regional mean growing season beginning date, and a 1 °C increase in regional mean autumn temperature causes a delay of 2.3 days in regional mean growing season end date. A 1 °C increase in regional annual mean temperature induces an extension of 8.7 days in regional mean growing season length. Over the 52 stations, response of the beginning date to spring temperature depends mainly on local annual mean temperature and geographic coordinates plus elevation. Namely, a 1 °C increase in spring temperature induces a larger advancement of the beginning date at warmer locations with lower latitudes and further west longitudes than at colder locations with higher latitudes and further east longitudes, while a 1 °C increase in spring temperature causes a larger advancement of the beginning date at higher than at lower elevations.

  7. Temperature and geographic attribution of change in the Taraxacum mongolicum growing season from 1990 to 2009 in eastern China's temperate zone

    NASA Astrophysics Data System (ADS)

    Chen, Xiaoqiu; Tian, Youhua; Xu, Lin

    2015-10-01

    Using leaf unfolding and leaf coloration data of a widely distributed herbaceous species, Taraxacum mongolicum, we detected linear trend and temperature response of the growing season at 52 stations from 1990 to 2009. Across the research region, the mean growing season beginning date marginal significantly advanced at a rate of -2.1 days per decade, while the mean growing season end date was significantly delayed at a rate of 3.1 days per decade. The mean growing season length was significantly prolonged at a rate of 5.1 days per decade. Over the 52 stations, linear trends of the beginning date correlate negatively with linear trends of spring temperature, whereas linear trends of the end date and length correlate positively with linear trends of autumn temperature and annual mean temperature. Moreover, the growing season linear trends are also closely related to the growing season responses to temperature and geographic coordinates plus elevation. Regarding growing season responses to temperature, a 1 °C increase in regional mean spring temperature results in an advancement of 2.1 days in regional mean growing season beginning date, and a 1 °C increase in regional mean autumn temperature causes a delay of 2.3 days in regional mean growing season end date. A 1 °C increase in regional annual mean temperature induces an extension of 8.7 days in regional mean growing season length. Over the 52 stations, response of the beginning date to spring temperature depends mainly on local annual mean temperature and geographic coordinates plus elevation. Namely, a 1 °C increase in spring temperature induces a larger advancement of the beginning date at warmer locations with lower latitudes and further west longitudes than at colder locations with higher latitudes and further east longitudes, while a 1 °C increase in spring temperature causes a larger advancement of the beginning date at higher than at lower elevations.

  8. [Quantifying direct N2O emissions from paddy fields during rice growing season in China: model establishment].

    PubMed

    Zou, Jian-Wen; Qin, Yan-Mei; Liu, Shu-Wei

    2009-02-15

    Various water management regimes, such as continuous flooding (F), flooding-midseason drainage-reflooding (F-D-F), and flooding-midseason drainage-reflooding-moist intermittent irrigation but without water logging (F-D-F-M), are currently practiced in paddy rice production in China. These water regimes have incurred a sensitive change in direct N2O emission from rice paddy fields. In order to establish statistical models quantifying the country-specific emission factor and background emission of N2O in paddy fields during the rice growing season, we compiled and statistically analyzed field data on 71 N2O measurements from 17 field studies that were published in peer-reviewed Chinese and English journals. For each field study, we documented the seasonal N2O emission, the type and amount of organic amendment and fertilizer nitrogen application, the water management regime, the drainage duration, the field location and cropping season. Seasonal total N2O was, on average, equivalent to 0.02% of the nitrogen applied in the continuous flooding rice paddies. Under the water regime of F-D-F or the F-D-F-M, seasonal N2O emissions increased with N fertilizer applied in rice paddies. Applying an Ordinary Least Square (OLS) linear regression model resulted in an emission factor of 0.42% for N2O, and in unpronounced background N2 O emission under the water regime of F-D-F. Under the F-D-F-M water regime, N2O emission factor and N2O-N background emission were estimated to be 0.73% and 0.79 kg x hm(-2) during the paddy rice growing season, respectively. After considering three different water regimes in rice paddies in China, the emission factor of N for N2O and N2O-N background emission averaged 0.54% and 0.43 kg x hm(-2). The results of this study suggest that paddy rice relative to upland crop production could have contributed to mitigating N2O emissions from agriculture in China. The emission factor of N for N2O and its background emissions can be directly adopted to develop

  9. Antifungal activities of selected aromatic plants growing wild in Greece.

    PubMed

    Soković, M; Tzakou, O; Pitarokili, D; Couladis, M

    2002-10-01

    Essential oils of Origanum onites, Satureja thymbra, Salvia fruticosa (Greek sage), and Salvia pomifera subsp. calycina plants growing wild in Greece and their components carvacrol, camphor, and 1,8-cineole, were assayed for antifungal activity against 13 fungal species. Among the fungi tested were food poisoning, plant, animals and human pathogenic species. The oils presented various degrees of inhibition against all the fungi investigated. The highest and broadest activity was shown by the carvacrol content oils (O. onites and S. thymbra), while the oil of sage was the least effective. Carvacrol exhibited the highest and 1,8-cineole the lowest level of antifungal activity among the components tested. PMID:12428445

  10. Are BVOC exchanges in agricultural ecosystems overestimated? Insights from fluxes measured in a maize field over a whole growing season

    NASA Astrophysics Data System (ADS)

    Bachy, Aurélie; Aubinet, Marc; Schoon, Niels; Amelynck, Crist; Bodson, Bernard; Moureaux, Christine; Heinesch, Bernard

    2016-04-01

    Although maize is the second most important crop worldwide, and the most important C4 crop, no study on biogenic volatile organic compounds (BVOCs) has yet been conducted on this crop at ecosystem scale and over a whole growing season. This has led to large uncertainties in cropland BVOC emission estimations. This paper seeks to fill this gap by presenting, for the first time, BVOC fluxes measured in a maize field at ecosystem scale (using the disjunct eddy covariance by mass scanning technique) over a whole growing season in Belgium. The maize field emitted mainly methanol, although exchanges were bi-directional. The second most exchanged compound was acetic acid, which was taken up mainly in the growing season. Bi-directional exchanges of acetaldehyde, acetone and other oxygenated VOCs also occurred, whereas the terpenes, benzene and toluene exchanges were small, albeit significant. Surprisingly, BVOC exchanges were of the same order of magnitude on bare soil and on well developed vegetation, suggesting that soil is a major BVOC reservoir in agricultural ecosystems. Quantitatively, the maize BVOC emissions observed were lower than those reported in other maize, crops and grasses studies. The standard emission factors (SEFs) estimated in this study (231 ± 19 µg m-2 h-1 for methanol, 8 ± 5 µg m-2 h-1 for isoprene and 4 ± 6 µg m-2 h-1 for monoterpenes) were also much lower than those currently used by models for C4 crops, particularly for terpenes. These results suggest that maize fields are small BVOC exchangers in north-western Europe, with a lower BVOC emission impact than that modelled for growing C4 crops in this part of the world. They also reveal the high variability in BVOC exchanges across world regions for maize and suggest that SEFs should be estimated for each region separately.

  11. Xanthine oxidase inhibitory activity of Hungarian wild-growing mushrooms.

    PubMed

    Ványolós, Attila; Orbán-Gyapai, Orsolya; Hohmann, Judit

    2014-08-01

    Mushrooms represent a remarkable and yet largely unexplored source of new, biologically active natural products. In this work, we report on the xanthine oxidase (XO) inhibitory activity of 47 wild-growing mushrooms native to Hungary. Aqueous and organic (n-hexane, chloroform, and 50% methanol) extracts of selected mushrooms from different families were screened for their XO inhibitory activities. Among the 188 extracts investigated, the chloroform and 50% methanol fractions proved to be the most effective. Some species exhibited high inhibitory activity, e.g., Hypholoma fasciculare (IC50  =67.76 ± 11.05 µg/mL), Suillus grevillei (IC50  =13.28 ± 1.58 µg/mL), and Tricholoma populinum (IC50  =85.08 ± 15.02 µg/mL); others demonstrated moderate or weak activity. Additional studies are warranted to characterize the compounds responsible for the XO inhibitory activity of mushroom extracts.

  12. Effects of leaf display on light interception and apparent photosynthesis in two contrasting Populus cultivars during their second growing season.

    PubMed

    Dickmann, D. I.; Michael, D. A.; Isebrands, J. G.; Westin, S.

    1990-12-01

    Effects of the contrasting leaf display of poplar cultivars Eugenei (Populus x euramericana) and Tristis (P. tristis x P. balsamifera) on light interception and photosynthesis were studied in the second year of growth in an irrigated plantation near Rhinelander, Wisconsin, USA (lat. 45 degrees N). Leaves on the current terminal (CT) and on proleptic branches were measured between 0900 and 1500 h on five clear days from June to September 1980. Leaf orientation-based differences between these cultivars were evident as the second growing season progressed and the crowns of the trees in the plantation grew together. Leaves of Eugenei are erectophile or tilted from the horizontal. In this cultivar light penetrated throughout the crown; many leaves on the lowest branches were illuminated as fully as those on the upper CT and had higher photosynthetic rates than equivalent leaves in Tristis. However, by early September many of the lower branches on Eugenei trees had abscised. In the planophile Tristis, adaxial photon flux densities (PPFD) of leaves on the lower portion of the CT and on branches were only a fraction of those measured on the upper CT. This pattern became more extreme as the season progressed. Few of the lower branches of Tristis abscised during the growing season. Photosynthesis rates, especially on a whole-leaf basis, were closely related to incident PPFDs in both cultivars. The ecological significance of these results are discussed, as well as the hypothesized effect of leaf inclination on crop productivity.

  13. Influence of growing season on phenolic compounds and antioxidant properties of grape berries from vines grown in subtropical climate.

    PubMed

    Xu, Changmou; Zhang, Yali; Zhu, Lei; Huang, Yu; Lu, Jiang

    2011-02-23

    The influence of growing season (winter vs summer) on the synthesis and accumulation of phenolic compounds and antioxidant properties was studied in five grape cultivars for three consecutive years. Four phenolic compound parameters (total phenols, flavonoids, flavan-3-ols, and anthocyanins) and three antioxidant property parameters [2,2-diphenyl-1-picrylhydrazyl radical scavenging, 2,2-azinobis(3-ethylbenzothiazolinesulfonic acid) radical scavenging, and ferric reducing antioxidant power] were investigated. Results showed that both phenolic compounds and antioxidant properties in the seed and skin of winter berries were significantly (p < 0.05) higher than those of summer berries for all of the cultivars investigated. The anthocyanin profiles of berry skins appeared to be extremely consistent in different years for the same crop, whereas they varied greatly between the two crops within the same year (winter vs summer). Winter berries contained richer glucosides of delphinidin, cyanidin, peonidin, and malvidin than summer berries. These seasonal variations of phenolic compounds and antioxidant properties on grape berries were largely contributed by climatic factors such as temperature, solar radiation, rainfall, and hydrothermic coefficient between different growing seasons.

  14. Seasonal photosynthetic activity in evergreen conifer leaves monitored with spectral reflectance

    NASA Astrophysics Data System (ADS)

    Wong, C. Y.; Gamon, J. A.

    2013-12-01

    productivity. Furthermore, the seasonal transitions between photosynthetically active and inactive states can be clearly detected by the PRI. These findings have implications for using remote sensing to detect dynamics in photosynthetic activity in response to changing growing season length in northern latitudes.

  15. High-Frequency Measurements of Methane Ebullition Over a Growing Season at a Temperate Peatland Site

    NASA Technical Reports Server (NTRS)

    Goodrich, Jordan P.; Varner, Ruth K.; Frolking, Steve; Duncan, Bryan N.; Crill, Patrick M.

    2011-01-01

    Bubbles can contribute a significant fraction of methane emissions fr om wetlands; however the range of reported fractions is very large an d accurate characterization of this pathway has proven difficult. Her e we show that continuous automated flux chambers combined with an in tegrated cavity output spectroscopy (ICOS) instrument allow us to qua ntify both CH4 ebullition rate and magnitude. For a temperate poor f en in 2009, ebullition rate varied on hourly to seasonal time scales. A diel pattern in ebullition was identified with peak release occurr ing between 20:00 and 06:00 local time, though steady fluxes (i.e., t hose with a linear increase in chamber headspace CH4 concentration) d id not exhibit diel variability. Seasonal mean ebullition rates peake d at 843.5 +/- 384.2 events m(exp -2)/d during the summer, with a me an magnitude of 0.19 mg CH4 released in each event.

  16. Impacts of climate change on corn yield and the length of corn growing season in U.S. Corn Belt

    NASA Astrophysics Data System (ADS)

    Niyogi, D.; Liu, X.; Takle, E. S.; Anderson, C.; Andresen, J.; Alagarswamy, G.; Gramig, B. M.; Doering, O.

    2015-12-01

    This study is a result of a USDA sponsored project titled Useful to Usable (U2U): "Transforming Climate Variability and Change Information for Cereal Crop Producers". The objective of this project is to improve farm resilience and profitability in the U.S. Corn Belt region by transforming existing meteorological dataset into usable knowledge and tools for the agricultural community. In this study, we conducted the Hybrid-Maize corn growth simulation model at 18 sites across the U.S. Corn Belt with 5 CMIP5 (Coupled Model Intercomparison Project) climate models. The crop model was running for two time periods: 1981-2010 ('current') and 2041-2070 ('future'). We also developed a "delta" method, which combines the current climate variability with the "mean" model projected climate change. The results indicate that under the 'future' climate, growing degree days (GDD) projected corn growing season (from planting date reach to maturity required GDD) are shortened due to the increasing of mean temperature. Compare to the contemporary simulations, the shorter growing season under "future" scenario brings lower attainable yields if farmers using the same cultivar. This presentation will focus on the details about the model simulations, the interactive process employed in developing the simulations, the implications of the results, the uncertainties, and the lessons learned.

  17. Effect of environmental stress factors on ecophysiological traits and susceptibility to pathogens of five Populus clones throughout the growing season.

    PubMed

    Fernàndez-Martínez, Jordi; Zacchini, Massimo; Elena, Georgina; Fernández-Marín, Beatriz; Fleck, Isabel

    2013-06-01

    The variability of ecophysiological traits associated with productivity (e.g., water relations, leaf structure, photosynthesis and nitrogen (N) content) and susceptibility to fungal and insect infection were investigated in five poplar clones (Populus deltoides Batr.-Lux clone; Populus nigra L.-58-861 clone and Populus × canadensis Mönch.-Luisa Avanzo, I-214 and Adige clones) during their growing season. The objective of the study was to determine their physiological responses under summer constraints (characteristic of the Mediterranean climate) and to propose clone candidates for environmental restoration activities such as phytoremediation. Relative water content, the radiometric water index and (13)C isotope discrimination (Δ(13)C) results reflected improved water relations in Adige and Lux during summer drought. Leaf structural parameters such as leaf area, leaf mass per area, density (D) and thickness (T) indicated poorer structural adaptations to summer drought in clone 58-861. Nitrogen content and Δ(13)C results pointed to a stomatal component as the main limitant of photosynthesis in all clones. Adige and Lux showed enhanced photoprotection as indicated by the size and the de-epoxidation index of the xanthophyll-cycle pool, and also improved antioxidant defence displayed by higher ascorbate, reduced glutathione, total phenolics and α-tocopherol levels. Photoprotective and antioxidative responses allowed all clones to maintain a high maximum quantum yield of PSII (Fv/Fm) with the exception of Luisa Avanzo and 58-861 which experienced slight photoinhibition in late spring. The study of susceptibility to rust (Melampsora sp.) and lace bug (Monosteira unicostata Muls. and Rey) infections showed Adige and Lux to be the most tolerant. Overall, these two clones presented high adaptability to summer conditions and improved resistance to abiotic and biotic stress, thereby making them highly commendable clones for use in environmental remediation programmes.

  18. Dietary copper supplementation improves pelt characteristics of female silver fox (Vulpes fulva) during the winter fur-growing season.

    PubMed

    Zhong, Wei; Liu, Hanlu; Luo, Guoliang; Chang, Zhongjuan; Liu, Fenghua; Zhao, Jingbo; Li, Danli; Yue, Zhigang; Zhang, Haihua; Li, Guangyu

    2014-07-01

    Copper has an essential role in normal fur pigmentation and fur quality. This study evaluated the effects of cupric citrate (CuCit) supplementation on growth, nutrients metabolism and pelt characteristics of the female silver fox (Vulpes fulva). Fifty age-matched female silver foxes with similar body weights were randomly divided into five dietary groups for 58 days during the winter fur-growing season. The basal diet contained 4.92 mg/kg copper. Groups I-V were supplemented with 6, 30, 60, 90 or 150 mg Cu from CuCit per 1 kg dry matter basal diet. Serum alkaline phosphatase activity was significantly higher (P<0.05) in those fed 90 mg/kg Cu than those fed 150 mg/kg Cu. Pelt total thickness was significantly higher (P<0.05) in those fed 30 mg/kg Cu than foxes fed 6 mg/kg Cu supplemented diet, but were similar to the other groups. Length of guard hair was significantly lower (P<0.05) in those fed 90 mg/kg Cu than fed 6 mg/kg Cu and 30 mg/kg Cu, but were similar to the other groups. Length of underhair was significantly higher (P<0.05) in those fed 6 mg/kg Cu than those fed 90 mg/kg Cu, but was similar to the other groups. Considering decreasing environmental contamination and improving pelt performance, supplementing 30 mg/kg Cu from CuCit (actual copper 35 mg/kg dry matter) is appropriate for female silver fox.

  19. Landscape controls on the timing of spring, autumn, and growing season length in mid-Atlantic forests

    USGS Publications Warehouse

    Elmore, A.J.; Guinn, S.M.; Minsley, B.J.; Richardson, A.D.

    2012-01-01

    The timing of spring leaf development, trajectories of summer leaf area, and the timing of autumn senescence have profound impacts to the water, carbon, and energy balance of ecosystems, and are likely influenced by global climate change. Limited field-based and remote-sensing observations have suggested complex spatial patterns related to geographic features that influence climate. However, much of this variability occurs at spatial scales that inhibit a detailed understanding of even the dominant drivers. Recognizing these limitations, we used nonlinear inverse modeling of medium-resolution remote sensing data, organized by day of year, to explore the influence of climate-related landscape factors on the timing of spring and autumn leaf-area trajectories in mid-Atlantic, USA forests. We also examined the extent to which declining summer greenness (greendown) degrades the precision and accuracy of observations of autumn offset of greenness. Of the dominant drivers of landscape phenology, elevation was the strongest, explaining up to 70% of the spatial variation in the onset of greenness. Urban land cover was second in importance, influencing spring onset and autumn offset to a distance of 32 km from large cities. Distance to tidal water also influenced phenological timing, but only within ~5 km of shorelines. Additionally, we observed that (i) growing season length unexpectedly increases with increasing elevation at elevations below 275 m; (ii) along gradients in urban land cover, timing of autumn offset has a stronger effect on growing season length than does timing of spring onset; and (iii) summer greendown introduces bias and uncertainty into observations of the autumn offset of greenness. These results demonstrate the power of medium grain analyses of landscape-scale phenology for understanding environmental controls on growing season length, and predicting how these might be affected by climate change.

  20. Partitioning the grapevine growing season in the Douro Valley of Portugal: accumulated heat better than calendar dates

    NASA Astrophysics Data System (ADS)

    Real, António C.; Borges, José; Cabral, J. Sarsfield; Jones, Gregory V.

    2015-08-01

    Temperature and water status profiles during the growing season are the most important factors influencing the ripening of wine grapes. To model weather influences on the quality and productivity of the vintages, it is necessary to partition the growing season into smaller growth intervals in which weather variables are evaluated. A significant part of past and ongoing research on the relationships between weather and wine quality uses calendar-defined intervals to partition the growing season. The phenology of grapevines is not determined by calendar dates but by several factors such as accumulated heat. To examine the accuracy of different approaches, this work analyzed the difference in average temperature and accumulated precipitation using growth intervals with boundaries defined by means of estimated historical phenological dates and intervals defined by means of accumulated heat or average calendar dates of the Douro Valley of Portugal. The results show that in situations where there is an absence of historical phenological dates and/or no available data that makes the estimation of those dates possible, it is more accurate to use grapevine heat requirements than calendar dates to define growth interval boundaries. Additionally, we analyzed the ability of the length of growth intervals with boundaries based on grapevine heat requirements to differentiate the best from the worst vintage years with the results showing that vintage quality is strongly related to the phenological events. Finally, we analyzed the variability of growth interval lengths in the Douro Valley during 1980-2009 with the results showing a tendency for earlier grapevine physiology.

  1. [Effects of precipitation variation on growing seasonal dynamics of soil microbial biomass in broadleaved Korean pine mixed forest].

    PubMed

    Wang, Ning; Wang, Mei-ju; Li, Shi-lan; Wang, Nan-nan; Feng, Fu-juan; Han, Shi-jie

    2015-05-01

    Broadleaved Korean pine mixed forest is the zonal climax vegetation in Northeast China and it plays a significant role in maintaining the ecological security. Changbai Mountains is a suitable region to study the positive and negative feedback mechanisms of temperate forest for precipitation variation. This study analyzed responses of soil microbial biomass carbon (SMBC) and microbial biomass nitrogen (SMBN) to precipitation variation (± 30%) in original broadleaved Korean pine mixed forest of Changbai Mountains. The results showed that, during the growing seasons (from May to September), the averages of SMBC and SMBN were 879.09 and 100.03 mg · kg(-1), respectively. Moreover, both of these two parameters gradually decreased with the soil depth. The contents of SMBC and SMBN all increased with the increasing precipitation, and the changes of SMBC and SMBN in the 0-5 cm soil layer were stronger than in the 5-10 cm soil layer. The value of SMBC/SMBN declined with the increase of precipitation. The precipitation variation significantly influenced the means of SMBC and SMBN. Compared with precipitation reduction, precipitation enhancement affected the indices much significantly. Both SMBC and SMBN showed similar seasonal patterns, which were the lowest in May, and after that, they increased and then decreased and increased again, showing 1-2 peaks in the growing season. However, the value and occurring time of the peaks varied with the precipitation and soil layer, and the seasonal variations of SMBC and SMBN in the 0-5 cm soil layer were higher than in the 5-10 cm soil layer. SMBC and SMBN had significant positive correlation with organic matter and total nitrogen content. The variances of soil physical and chemical properties caused by precipitation variation were closely related with the difference in spatial-temporal patterns of the soil microbial biomass in the forest. In conclusion, the precipitation variations could cause the change of the soil microbial

  2. [Effects of precipitation variation on growing seasonal dynamics of soil microbial biomass in broadleaved Korean pine mixed forest].

    PubMed

    Wang, Ning; Wang, Mei-ju; Li, Shi-lan; Wang, Nan-nan; Feng, Fu-juan; Han, Shi-jie

    2015-05-01

    Broadleaved Korean pine mixed forest is the zonal climax vegetation in Northeast China and it plays a significant role in maintaining the ecological security. Changbai Mountains is a suitable region to study the positive and negative feedback mechanisms of temperate forest for precipitation variation. This study analyzed responses of soil microbial biomass carbon (SMBC) and microbial biomass nitrogen (SMBN) to precipitation variation (± 30%) in original broadleaved Korean pine mixed forest of Changbai Mountains. The results showed that, during the growing seasons (from May to September), the averages of SMBC and SMBN were 879.09 and 100.03 mg · kg(-1), respectively. Moreover, both of these two parameters gradually decreased with the soil depth. The contents of SMBC and SMBN all increased with the increasing precipitation, and the changes of SMBC and SMBN in the 0-5 cm soil layer were stronger than in the 5-10 cm soil layer. The value of SMBC/SMBN declined with the increase of precipitation. The precipitation variation significantly influenced the means of SMBC and SMBN. Compared with precipitation reduction, precipitation enhancement affected the indices much significantly. Both SMBC and SMBN showed similar seasonal patterns, which were the lowest in May, and after that, they increased and then decreased and increased again, showing 1-2 peaks in the growing season. However, the value and occurring time of the peaks varied with the precipitation and soil layer, and the seasonal variations of SMBC and SMBN in the 0-5 cm soil layer were higher than in the 5-10 cm soil layer. SMBC and SMBN had significant positive correlation with organic matter and total nitrogen content. The variances of soil physical and chemical properties caused by precipitation variation were closely related with the difference in spatial-temporal patterns of the soil microbial biomass in the forest. In conclusion, the precipitation variations could cause the change of the soil microbial

  3. Antiurease activity of plants growing in the Czech Republic.

    PubMed

    Hřibová, Petra; Khazneh, Elian; Žemlička, Milan; Švajdlenka, Emil; Ghoneim, Mohammed M; Elokely, Khaled M; Ross, Samir A

    2014-01-01

    The antiurease activity of the aqueous extracts of 42 plants growing in the Czech Republic was investigated. A phenol-hypochlorite reaction was used for the determination of ammonia produced by urease. The inhibitory activity of the extracts at a concentration of 0.2 mg/mL varied from 17.8% to 80.0%. Extracts from six Potentilla species expressed inhibitory activity against jack bean urease. They were further investigated for their phenolic constituents and the major compounds were subjected to molecular docking. The results revealed that both jack bean urease and Helicobacter pylori urease were inhibited by quercetin-3-O-β-D-galactopyranoside-6″-gallate (1), myricetin-3-O-β-D-glucuronide (2), tiliroside (3) and B-type procyanidin (4). The antiurease activity of the investigated Potentilla species is probably due to the presence of complex phenolic constituents such as flavonoid glycosides and catechin dimers.

  4. The variation of methane flux rates from boreal tree species at the beginning of the growing season

    NASA Astrophysics Data System (ADS)

    Haikarainen, Iikka; Halmeenmäki, Elisa; Machacova, Katerina; Pihlatie, Mari

    2016-04-01

    Boreal forests are considered as net sink for atmospheric methane (CH4) because of the CH4 oxidizing bacteria in the aerobic soil layer. However, within the last decades it has become more evident that trees play an important role in the global CH4 budget by offering pathways for anaerobically produced CH4 from deeper soil layers to the atmosphere. Furthermore, trees may also act as independent sources of CH4. To confirm magnitude, variability and the origin of the tree mediated CH4 emissions more research is needed, especially in boreal forests which have been in a minority in such investigation. We measured tree stem and shoot CH4 exchange of three boreal tree species at the beginning of the growing season (13.4.-13.6.2015) at SMEAR II station in Hyytiälä, located in southern Finland (61° 51'N, 24° 17'E, 181 asl). The fluxes were measured from silver birch (Betula pendula), downy birch (B. pubescens) and Norway spruce (Picea abies) on two sites with differing soil type and characteristics (paludified and mineral soil), vegetation and forest structure by using the static chamber technique. Scaffold towers were used for measurements at multiple stem heights and shoots. The aim was to study the vertical profile of CH4 fluxes at stem and shoot level and compare these fluxes among the studied species, and to observe temporal changes in CH4 flux over the beginning of the growing season. We found that all the trees emitted CH4 from their stems and shoots. Overall, the birches showed higher emissions compared to the spruces. The emission rates were considerably larger in the lower parts of the birch stems than upper parts, and these emissions increased during the growing season. The spruces had more variation in the stem CH4 flux, but the emission rates of the upper parts of the stem exceeded the birch emissions at the same height. The shoot fluxes of all the studied trees indicated variable CH4 emissions without a clear pattern regarding the vertical profile and

  5. Exploring the correlation between Southern Africa NDVI and Pacific sea surface temperatures: Results for the 1998 maize growing season

    USGS Publications Warehouse

    Verdin, J.; Funk, C.; Klaver, R.; Roberts, D.

    1999-01-01

    Several studies have identified statistically significant correlations between Pacific sea surface temperature anomalies and NDVI anomalies in Southern Africa. The potential predictive value of the relationship was explored for the 1998 maize growing season. Cross-validation techniques suggested a more useful relationship for regions of wet anomaly than for regions of dry anomaly. Observed 1998 NDVI anomaly patterns were consistent with this result. Wet anomalies were observed as expected, but wide areas of expected dry anomalies exhibited average or above-average greeness.

  6. Plot-level Microtopographical Controls on Arctic Growing Season and Fall Shoulder Season Soil CO2 Flux

    NASA Astrophysics Data System (ADS)

    Wilkman, E.; Oechel, W. C.; Zona, D.

    2015-12-01

    Permafrost soils are among the most obvious environments in which current constraints on decomposition are likely to change as a result of climatic alterations, potentially exposing large amounts of previously stored carbon (C) to microbial degradation and emission during the next few decades (Davidson & Janssens, 2006). As a best estimate, the soils of the circumpolar Arctic store over 1,035 ± 150 Pg C in the near surface (0-3 m), approximately twice the amount of C that is currently in the atmosphere (Tarnocai et al., 2009; Hugelius et al., 2014). Currently, however, much of this previously stored carbon is at risk of loss to the atmosphere due to accelerated soil organic matter decomposition in warmer future climates (Dorrepaal et al., 2009; Schuur et al., 2015). Polygonization, a predominant cryogenic process, produces micro-topographical and hydrological heterogeneity, as polygon rims produce lower water tables and drier conditions and low polygon centers produce higher water tables and wetter conditions (Brown et al., 1980). As climate models increasingly suggest that current warming trends in the Arctic (4-8 °C higher annual surface air temperatures) will continue by century's end, C cycling in these northern climes may be further amplified (IPCC, 2013). Much uncertainty remains in regard to the spatial and temporal extent of CO2 emissions from these systems, especially in view of the potential for modifications to C cycling in response to increased warming and deeper summer thawing of the active soil layer (Mastepanov et al., 2013). Therefore, an LI-8100 Automated Soil Flux System (LI-COR Biosciences) was deployed in Barrow, AK, to gather high temporal frequency soil CO2 fluxes from a wet sedge tundra ecosystem. Dark chamber fluxes were gathered from 5 microtopographical habitats (designated flat, high, low, polygon rim, and polygon troughs) to calculate daily average, diurnal, and monthly respiratory fluxes. With the addition of concurrently gathered

  7. Environmental and societal consequences of a possible CO/sub 2/-induced climate change. Volume II, Part 8. Impacts of rising atmospheric carbon dioxide levels on agricultural growing seasons and crop water use efficiencies

    SciTech Connect

    Newman, J. E.

    1982-09-01

    The researchable areas addressed relate to the possible impacts of climate change on agricultural growing seasons and crop adaptation responses on a global basis. The research activities proposed are divided into the following two main areas of investigation: anticipated climate change impacts on the physical environmental characteristics of the agricultural growing seasons and, the most probable food crop responses to the possible changes in atmospheric CO/sub 2/ levels in plant environments. The main physical environmental impacts considered are the changes in temperature, or more directly, thermal energy levels and the growing season evapotranspiration-precipitation balances. The resulting food crop, commercial forest and rangeland species response impacts addressed relate to potential geographical shifts in agricultural growing seasons as determined by the length in days of the frost free period, thermal energy changes and water balance changes. In addition, the interaction of possible changes in plant water use efficiencies during the growing season in relationship to changing atmospheric CO/sub 2/ concentrations, is also considered under the scenario of global warming due to increases in atmospheric CO/sub 2/ concentration. These proposed research investigations are followed by adaptive response evaluations.

  8. Steers grazing blue grama rangeland throughout the growing season. II. Site and extent of digestion and microbial protein synthesis.

    PubMed

    Funk, M A; Galyean, M L; Branine, M E

    1987-11-01

    Effects of advancing forage maturity and drought-induced summer dormancy on site and extent of digestion and microbial protein synthesis in beef steers grazing native blue grama rangeland were evaluated in four sampling periods. Five steers (avg initial wt 227 kg) fitted with ruminal, duodenal and ileal cannulae and three steers cannulated at the esophagus freely grazed a 12-ha study pasture. Sampling periods lasted 11 d and started June 2, which was during the early growing season (EGS); June 22, during early summer dormancy (ESD); July 21, during late summer dormancy (LSD); and August 25, 1985, during the late growing season (LGS). Dietary N content was lower (P less than .05) in ESD and LSD than in EGS and LGS. Neutral detergent fiber (NDF) content was lower (P less than .05) in EGS than in other sampling periods. Ruminal organic matter (OM) digestion was lower (P less than .05) in ESD than in EGS, probably because of increased dietary NDF and lower N content. Ruminal OM digestion was greater (P less than .05) in LSD and LGS than in ESD because of increased fiber digestion. Neutral detergent fiber and acid detergent fiber (ADF) digestion occurring in the rumen was greater (P less than .05) in LSD and LGS than in EGS and ESD. Organic matter digestion in the small intestine and OM, NDF and ADF digestion in the hindgut were similar for all sampling periods. Over 90% of the fiber digestion occurred ruminally.(ABSTRACT TRUNCATED AT 250 WORDS)

  9. Improving crop biomass through asynchronous assimilation of LAI and soil moisture during multiple growing seasons of corn

    NASA Astrophysics Data System (ADS)

    Bongiovanni, T. E.; Nagarajan, K.; Jones, J. W.; Monsivais Huertero, A.; Judge, J.

    2010-12-01

    Crop biomass is an important indicator of the health of a plant and is also critical for various remote sensing algorithms. In addition, it determines water uptake by the roots, affecting the root zone soil moisture (RZSM). Typically, crop models are used to simulate growth and development in a growing season and estimate biomass and yield. However large uncertainties in these estimates occur over time due to errors in computation, initialization conditions, forcings, and model parameters. Such uncertainties can be significantly reduced by assimilating in situ and/or remotely sensed observations. Satellite-based LAI and near-surface soil moisture (SM) are available weekly and 3 days, respectively. In this study, an EnKF-based assimilation algorithm was implemented to improve crop biomass using the Decision Support System for Agrotechnology Transfer (DSSAT) Cropping System Model. In situ observations of weekly LAI and every 3-day SM were assimilated asynchronously to update model estimates of LAI, RZSM, and crop biomass. The in situ observations were obtained from intensive field experiments during three seasons of sweet corn grown in North Central Florida. The impact of different assimilation scenarios for crop biomass was determined by the root mean squared difference and the standard deviation between the model estimates and observations during the seasons.

  10. Investigating the Persistence of a Snowpack Sublimation Stable Isotope Signal in Tree Xylem Water during the Growing Season

    NASA Astrophysics Data System (ADS)

    Schulze, E. S.; Bowling, D. R.

    2014-12-01

    Previous work identified a riparian meadow in the Rocky Mountains where streamside box elder (Acer negundo) trees did not use stream water, the most reliable and readily available source. A follow-up study showed that the water used by trees appears to be more evaporatively enriched than all available measured sources, including stream water, precipitation-derived soil water, and groundwater. While it is unlikely that there is a missing pool of water these trees are accessing, they may be tapping into a distinct subset of the bulk soil water available, possibly derived from much colder and older snowmelt. In this study, we investigated whether snowpack sublimation and subsequent melt water may impart an enriched isotopic signature that persists throughout the following growing season in less-mobile soil water pools. Profile samples of the snowpack, bulk melt water, and early season soil lysimeter water were collected throughout the winter and analyzed for hydrogen and oxygen stable isotopes. As snow began to melt in the spring, water samples for isotope analysis were taken from soil profiles, stream water, groundwater, and stems. Although sublimation likely occurred at the site, such processes did not impart an evaporative isotope enrichment on the snowpack throughout the season. Both snow pack and melt water remained closely tied to the local meteoric water line as they infiltrated soil. These findings suggest that snowpack sublimation processes preceding melt water infiltration are not the source of evaporative enrichment in tree water at our site.

  11. A comparative synoptic climatology of cool-season rainfall in major grain-growing regions of southern Australia

    NASA Astrophysics Data System (ADS)

    Pook, Michael J.; Risbey, James S.; McIntosh, Peter C.

    2014-08-01

    Two distinct synoptic weather systems, cut-off lows and fronts, deliver most of the cool-season rainfall to the cropping regions of southern Australia. A comparative synoptic climatology of daily rainfall events over approximately five decades reveals both spatial and temporal variations of the dominant synoptic types. The rainfall characteristics and associated large-scale drivers differ between the two synoptic types. Understanding regional rainfall depends on understanding these differences. Cut-off lows contribute one half of growing season rainfall in southeast Australia, while frontal systems associated with Southern Ocean depressions contribute about a third. The proportions are reversed in the Central Wheat Belt (CWB) of Western Australia where Southern Ocean fronts are the dominant source of growing season rainfall. In the southern island state of Tasmania, topography strongly influences the outcome with cut-off lows contributing about half the rainfall near the east coast and fronts dominating a short distance to the west. Cut-off lows generally contribute their highest proportion of rainfall in the austral autumn and spring while frontal rainfall is at its maximum in late winter. Cut-off low rainfall contributes more strongly in percentage terms to the recent decline in rainfall. The distribution of synoptic types is explained by the dominant long-wave structure in the winter half of the year. The major trough near Western Australia favours frontogenesis to the southwest of the CWB but fronts moving out of the region encounter a persistent meridional ridge in the Tasman Sea where there is a high frequency of blocking events.

  12. Spatiotemporal properties of growing season indices during 1961-2010 and possible association with agroclimatological regionalization of dominant crops in Xinjiang, China

    NASA Astrophysics Data System (ADS)

    Ci, Hui; Zhang, Qiang; Singh, Vijay P.; Xiao, Mingzhong; Liu, Lin

    2016-08-01

    Variations of frost days and growing season length (GSL) have been drawing increasing attention due to their impact on agriculture. The Xinjiang region in China is climatically an arid region and plays an important role in agriculture development. In this study, the GSL and frost events are analyzed in both space and time, based on the daily minimum, mean and maximum air surface temperature data covering a period of 1961-2010. Results indicate that: (1) a significant lengthening of GSL is detected during 1961-2010 in Xinjiang, China. The increasing rate of GSL over Xinjiang is about 2.5 days per decade. Besides, the starting time of growing season is 0.7 days earlier per decade and the ending time is 1.6 days later per decade. Generally, GSL in southern Xinjiang has larger increasing magnitude when compared to other regions of Xinjiang; (2) longer GSL and larger changing magnitude of growing season start (GSS), growing season end (GSE) and GSL in southern Xinjiang implies higher sensitivity of the growing season response to climate warming. Besides, GSL is in close relation with latitude, and higher latitude usually corresponds to later start and earlier end of growing season, and hence shorter GSL. In general, a northward increase of 1° latitude triggers an 8-day delay of the starting time of growing season, 6-day advance of the ending time of growing season, and thus the GSL is 14 days shorter; (3) GSL under different rates can reflect light and heat resources over Xinjiang. The GSL related to 80 % guarantee rate is 5-14 days shorter than the long-term annual mean GSL; (4) Lengthening of GSL has the potential to increase agricultural production. However, negative influences by climate warming, such as enhanced evapotranspiration, increasing weeds, insects, and pathogen-mediated plant diseases, should also be considered in planning, management and development of agriculture in Xinjiang.

  13. Growing season boundary layer climate and surface exchanges in a subarctic lichen woodland

    NASA Technical Reports Server (NTRS)

    Fitzjarrald, David R.; Moore, Kathleen E.

    1994-01-01

    Between June and August 1990, observations were made at two surface micrometeorological towers near Schefferville Quebec (54 deg 52 min N, 66 deg 40.5 min W), one in a fen and one in the subarctic lichen woodland, and at four surface climatological stations. Data from these surface stations were supplemented by regular radiosonde launches. Supporting measurements of radiative components and soil temperatures allowed heat and moisture balances to be obtained at two sites. The overall surface meteorological experiment design and results of micrometeorological observations made on a 30-m tower in the lichen woodland are presented here. Seasonal variation in the heat and water vapor transport characteristics illustrate the marked effect of the late summer climatological shift in air mass type. During the first half of the summer, average valley sidewalls only 100 m high are sufficient to channel winds along the valley in the entire convective boundary layer. Channeling effects at the surface, known for some time at the long-term climate station in Schefferville, are observed both at ridge top and in the valley, possibly the response of the flow to the NW-SE orientation of valleys in the region. Diurnal surface temperature amplitude at ridge top (approximately equal to 10 C) was found to be half that observed in the valley. Relatively large differences in precipitation among these stations and the climatological station at Schefferville airport were observed and attributed to the local topography. Eddy correlation observations of the heat, moisture and momentum transports were obtained from a 30-m tower above a sparse (approximately equal to 616 stems/ha) black spruce lichen woodland. Properties of the turbulent surface boundary layer agree well with previous wind tunnel studies over idealized rough surfaces. Daytime Bowen ratios of 2.5-3 are larger than those reported in previous studies. Surface layer flux data quality was assessed by looking at the surface layer heat

  14. Seasonal energy requirements and thermoregulation of growing pouched mice, Saccostomus campestris (Cricetidae)

    NASA Astrophysics Data System (ADS)

    Ellison, G. T. H.; Skinner, J. D.

    1991-06-01

    Pouched mice ( Saccostomus campestris) were born in captivity during January and March and subsequently maintained under long photoperiod (14 h light: 10 h dark) at 25°C. During their first winter (July) and the following summer (January) the pouched mice were exposed to natural photoperiod in an unheated laboratory for 3 weeks prior to measurement. The pouched mice continued to grow during the study, and were significantly heavier after summer exposure than after winter exposure 6 months earlier. Although this increase in body mass would result in a decline in their surface area to volume ratio there was no significant decline in minimal thermal conductance ( C m) and winter-exposed pouched mice had a relatively lower C m than expected. Meanwhile the smaller, winter-exposed animals displayed a significantly higher capacity for non-shivering thermogenesis, together with higher levels of basal metabolism than summer individuals. These differences were not solely attributable to the contrasting body mass of each group and it is therefore clear that S. campestris can increase thermoregulatory heat production, and modify heat loss following exposure to short photoperiod and cold during their first winter. Despite the significant increase in metabolism, the overall energy requirements of small, winter-exposed animals were significantly lower than those for heavier pouched mice following exposure to summer conditions. These results suggest that growing pouched mice can effectively adapt to lower temperature conditions during their first winter, yet accrue considerable overall savings in total energy requirements as a result of their smaller body mass.

  15. Integrating ground observations of phenology with remotely sensed measurements: A 2007 growing season experiment at Sevilleta LTER

    NASA Astrophysics Data System (ADS)

    Bradley, B.; Wetherill, K.; Vanderbilt, K.; Nickeson, J.

    2007-12-01

    The use of satellites to monitor land surface phenology is important for understanding local and regional ecosystem variability, identifying change over time, and potentially predicting ecosystem response to short and long-term changes in climate. However, the relationship between how phenology is expressed on the ground and how it is interpreted from satellites is poorly understood because phenological stages do not always correspond well to changes in spectral reflectance. Rather than focusing on phenological stages (e.g., first leaf, first flower), the ground measurements in this study focus on changes in ecosystem greenness during the 2007 growing season. We collected bi-monthly measurements of community greenness in two perennial grasslands at the Sevilleta National Wildlife Refuge in central New Mexico, a Long Term Ecological Research (LTER) site. One site is dominated by blue grama grass (Bouteloua gracilis); the other is dominated by black grama grass (Bouteloua eriopoda). Grama grasses grow during the summer/fall time period, with onset of greenness typically occurring mid-July and peak greenness occurring in September. Bi-monthly ground measurements were collected from July 2, 2007 - October 4, 2007 within systematically arrayed 30x30 cm quadrats. Within each quadrat, we recorded percent green cover (grass or forb), percent non- photosynthetic cover, and percent soil. A nadir oriented digital photograph was also taken of each quadrat, from which a greenness index was calculated. Field sampling was timed within two days of an ASTER satellite image acquisition. Here, we compare three greenness measurements from ground sampling, digital photography, and ASTER satellite imagery for the 2007 growing season. We show the degree of correlation between the three measurements through time and draw inferences about how satellite imagery can be used to assess ecosystem phenology. This study is an important first step in furthering the linkage between remotely sensed

  16. Growing Degree Vegetation Production Index (GDVPI): A Novel and Data-Driven Approach to Delimit Season Cycles

    NASA Astrophysics Data System (ADS)

    Graham, W. D.; Spruce, J.; Ross, K. W.; Gasser, J.; Grulke, N.

    2014-12-01

    Growing Degree Vegetation Production Index (GDVPI) is a parametric approach to delimiting vegetation seasonal growth and decline cycles using incremental growing degree days (GDD), and NASA's Moderate Resolution Imaging Spectroradiometer (MODIS) normalized difference vegetation index (NDVI) 8-day composite cumulative integral data. We obtain a specific location's daily minimum and maximum temperatures from the nearest National Oceanic and Atmospheric Administration (NOAA) weather stations posted on the National Climate Data Center (NCDC) Climate Data Online (CDO) archive and compute GDD. The date range for this study is January 1, 2000 through December 31, 2012. We employ a novel process, a repeating logistic product (RLP), to compensate for short-term weather variability and data drops from the recording stations and fit a curve to the median daily GDD values, adjusting for asymmetry, amplitude, and phase shift that minimize the sum of squared errors when comparing the observed and predicted GDD. The resulting curve, here referred to as the surrogate GDD, is the time-temperature phasing parameter used to convert Cartesian NDVI values into polar coordinate pairs, multiplying the NDVI values as the radial by the cosine and sine of the surrogate GDD as the angular. Depending on the vegetation type and the original NDVI curve, the polar NDVI curve may be nearly circular, kidney-shaped, or pear-shaped in the case of conifers, deciduous, or agriculture, respectively. We examine the points of tangency about the polar coordinate NDVI curve, identifying values of 1, 0, -1, or infinity, as each of these represent natural inflection points. Lines connecting the origin to each tangent point illustrate and quantify the parametrically segmentation of the growing season based on the GDD and NDVI ostensible dependency. Furthermore, the area contained by each segment represents the apparent vegetation production. A particular benefit is that the inflection points are determined

  17. Injury to apical meristem of cranberry by Dasineura oxycoccana (Diptera: Cecidomyiidae) reduces production of floral-units in the next growing season.

    PubMed

    Tewari, S; Buonaccorsi, J P; Averill, A L

    2012-08-01

    Cranberry tipworm, Dasineura oxycoccana Johnson (a gall-making fly), disrupts normal growth of cranberry (Vaccinium macrocarpon Aiton) by injuring the apical meristem of shoots or uprights. The impact of larval feeding injury on reproductive parameters of cranberry was determined, from one growing season to next, at upright (Maine and Massachusetts, 2008-2009) and plot levels (Massachusetts, 2009-2010 and 2010-2011). We also estimated the proportions of uprights injured because of tipworm feeding at several cranberry production sites (Massachusetts and Maine) and the proportions of uprights that produced flowers and fruits in the next growing season. Tipworm-injured uprights tagged at the end of the growing season did not produce floral-units (following year) across sites in both Massachusetts and Maine. There was significant variation among the sampled sites in the proportions of tipworm-injured uprights and also in the proportions of uprights with flowers in the next growing season (Massachusetts and Maine). A trend was apparent wherein sites with higher tipworm injury levels had relatively lower flowering proportions in the next growing season. However, sites in Massachusetts did not differ in the proportions of uprights that set fruit and in a replicated study, significant reduction in tipworm injury at plot level (using insecticide) did not impact flower and fruit production in the next growing season.

  18. Climatic warming above the Arctic Circle: are there trends in timing and length of the thermal growing season in Murmansk Region (Russia) between 1951 and 2012?

    PubMed

    Blinova, Ilona; Chmielewski, Frank-Michael

    2015-06-01

    Anomalies in the timing of the thermal growing season have become obvious in the NE part of Fennoscandia since 2000. They are in accordance with climatic changes reported for Europe and Fennoscandia. The actual length of the growing season reached 120 days on average, onset on 30 May and ending on 27 September (1981-2010). Shifts in the timing of the growing season and its mean prolongation by 18.5 days/62a are demonstrated for Murmansk Region (1951-2012). In this period, the onset of the growing season advanced by 7.1 days/62a, while the end was extended by 11.4 days/62a. The delay in the end of the growing season is similar to the entire Fennoscandian pattern but it has not been detected in the rest of Europe. The regional pattern of climatic regimes in Murmansk Region remained stable in comparison with earlier climatic maps (1971). However, the actual shifts in the timing of the growing season were more pronounced in colder (oceanic and mountainous) parts. Recent climatic trends could influence the retreat of the tundra zone and changes in the forest line. Losses of tundra biodiversity and enrichment of the northern taiga by southern species could be expected from present climatic trends.

  19. Climatic warming above the Arctic Circle: are there trends in timing and length of the thermal growing season in Murmansk Region (Russia) between 1951 and 2012?

    PubMed

    Blinova, Ilona; Chmielewski, Frank-Michael

    2015-06-01

    Anomalies in the timing of the thermal growing season have become obvious in the NE part of Fennoscandia since 2000. They are in accordance with climatic changes reported for Europe and Fennoscandia. The actual length of the growing season reached 120 days on average, onset on 30 May and ending on 27 September (1981-2010). Shifts in the timing of the growing season and its mean prolongation by 18.5 days/62a are demonstrated for Murmansk Region (1951-2012). In this period, the onset of the growing season advanced by 7.1 days/62a, while the end was extended by 11.4 days/62a. The delay in the end of the growing season is similar to the entire Fennoscandian pattern but it has not been detected in the rest of Europe. The regional pattern of climatic regimes in Murmansk Region remained stable in comparison with earlier climatic maps (1971). However, the actual shifts in the timing of the growing season were more pronounced in colder (oceanic and mountainous) parts. Recent climatic trends could influence the retreat of the tundra zone and changes in the forest line. Losses of tundra biodiversity and enrichment of the northern taiga by southern species could be expected from present climatic trends. PMID:25155187

  20. Verification of satellite radar remote sensing based estimates of boreal and subalpine growing seasons using an ecosystem process model and surface biophysical measurement network information

    NASA Technical Reports Server (NTRS)

    McDonald, K. C.; Kimball, J. S.; Zimmerman, R.

    2002-01-01

    We employ daily surface Radar backscatter data from the SeaWinds Ku-band Scatterometer onboard Quikscat to estimate landscape freeze-thaw state and associated length of the seasonal non-frozen period as a surrogate for determining the annual growing season across boreal and subalpine regions of North America for 2000 and 2001.

  1. [Quantifying direct N2O emissions from paddy fields during rice growing season in China: model and input data validation].

    PubMed

    Zou, Jian-Wen; Liu, Shu-Wei; Qin, Yan-Mei; Feng, De-Sheng; Zhu, Hui-Lin; Xu, Yong-Zhong

    2009-04-15

    The models on direct N2O emissions from rice paddies under different water regimes developed by the authors were validated against field measurements in China reported in 2005-2007 and in other regions. In flooding rice paddies (F), N2O emission predicted by the model was consistent with previous reports in other regions. Under the water regime of flooding-midseason drainage-reflooding (F-D-F), the model developed in this study was comparable to that established by using worldwide database. The models also well fitted N2O emissions from rice paddies under the water regime of flooding-midseason drainage-reflooding-moisture but without waterlogging (F-D-F-M) in China. Consistency of rice production data derived from the database of this study with those reported in previous studies suggests that the model input data of rice production had high reliability. The input data showed that water management and nitrogen input regimes have greatly changed in rice paddies since the 1950s. During the 1950s-1970s, about 20%-25% of the rice paddy was continuous water logging, and 75%-80% under the water regime of F-D-F. Since the 1980s, about 12%-16%, 77% and 7%-12% of paddy fields were under the water regimes of F, F-D-F and F-D-F-M, respectively. Total N input during the rice growing season averaged 87.49 kg x hm(-2) in the 1950s and 224.64 kg x hm(-2) in the 1990s. Chemical N input during the rice growing season has increased from 37.4 kg x hm(-2) in the 1950s to 198.8 kg x hm(-2) in the 1990s, accounting for 43% and 88% of the seasonal total N inputs, respectively. Manure N input was applied at stable rate, ranging from 45.2 kg x hm(-2) to 48.2 kg x hm(-2) during the 1950s-1970s, but thereafter it decreased over time. The contribution of manure N to total N inputs has decreased from 52% in the 1950s to 9% in the 1990s. Crop residue N retained during the rice growing season has increased from 4.9 kg x hm(-2) in the 1950s to 6.3 kg x hm(-2) in the 1980s. A high spatial

  2. Leaf ontogeny dominates the seasonal exchange of volatile organic compounds (VOC) in a SRC-poplar plantation during an entire growing season

    NASA Astrophysics Data System (ADS)

    Brilli, Federico; Gioli, Beniamino; Fares, Silvano; Zenone, Terenzio; Zona, Donatella; Gielen, Bert; Loreto, Francesco; Janssens, Ivan; Ceulemans, Reinhart

    2015-04-01

    The declining cost of many renewable energy technologies and changes in the prices of fossil fuels have recently encouraged governments policies to subsidize the use of biomass as a sustainable source of energy. Deciduous poplars (Populus spp.) trees are often selected for biomass production in short rotation coppiced (SRC) for their high CO2 photosynthetic assimilation rates and their capacity to develop dense canopies with high values of leaf area index (LAI). So far, observations and projections of seasonal variations of many VOC fluxes has been limited to strong isoprenoids emitting evergreen ecosystems such tropical and Mediterranean forests as well as Citrus and oil palm plantation, all having constant values of LAI. We run a long-term field campaign where the exchange of VOC, together with CO2 and water vapor was monitored during an entire growing season (June - November, 2012) above a SRC-based poplar plantation. Our results confirmed that isoprene and methanol were the most abundant fluxes emitted, accounting for more than 90% of the total carbon released in form of VOC. However, Northern climates characterized by fresh summertime temperatures and recurring precipitations favored poplar growth while inhibiting the development of isoprene emission that resulted in only 0.7% of the net ecosystem carbon exchange (NEE). Besides, measurements of a multitude of VOC fluxes by PTR-TOF-MS showed bi-directional exchange of oxygenated-VOC (OVOC) such as: formaldehyde, acetaldehyde, acetone, isoprene oxidation products (iox, namely MVK, MAC and MEK) as well as ethanol and formic acid. The application of Self Organizing Maps to visualize the relationship between the full time-series of many VOC fluxes and the observed seasonal variations of environmental, physiological and structural parameters proved the most abundant isoprene ad methanol fluxes to occur mainly on the hottest days under mid-high light intensities when also NEE and evapotraspiration reached the highest

  3. [Effects of nitrogen addition on available nitrogen content and acidification in cold-temperate coniferous forest soil in the growing season].

    PubMed

    Chen, Gao-Qi; Fu, Wa-Li; Luo, Ya-Chen; Gao, Wen-Long; Li, Sheng-Gong; Yang, Hao

    2014-12-01

    Based on a low-level and multi-form N addition control experiment, this study took cold-temperate coniferous forest in Daxing'an Ling as the research object. After long-term and continuous nitrogen addition in situ, the available nitrogen (NH4(+) -N & NO3(-) -N) contents and pH values of the soil (0-10 cm) were measured in the early growing season (May) and the peak growing season (August) in 2010, 2012 and 2013. The results showed that, the available nitrogen in the early and peak growing seasons was mainly NH4(+) -N which accounted for over 96% of the inorganic nitrogen content, while the content of NO3(-) -N was very low. With the time extension of nitrogen addition, the effects of nitrogen addition on the NH4(+) -N content in 0-10 cm soil were more obvious in the early growing season than that in the peak growing season, and the NH4(+) -N content was mainly affected by the type of nitrogen addition. On the contrary, the NO3(-) -N content in 0-10 cm soil was higher in the peak growing season than that in the early growing season. The effect of N input was obvious on NO3(-) -N content in both early and peak growing seasons, and low nitrogen treatment tended to promote the enrichment of NO3(-) -N. As time went on, the response of NH4(+) -N and NO3(-) -N content to N addition was changed from insignificant in the early stage to significant in the late stage. N addition had a significant impact on the pH value of the 0-10 cm soil in the early and peak growing seasons. The pH values of the soil with low nitrogen treatment and the soil in the peak growing season were relatively lower. With the extension of the nitrogen addition time, the response of pH value also turned from insignificant in the early stage to significant in the late stage. Because of the long-term and continuous nitrogen addition, the 0 - 10 cm soil in this cold-temperate coniferous forest was obviously acidified.

  4. Sensitivity of Active and Passive Microwave Observations to Soil Moisture during Growing Corn

    NASA Astrophysics Data System (ADS)

    Judge, J.; Monsivais-Huertero, A.; Liu, P.; De Roo, R. D.; England, A. W.; Nagarajan, K.

    2011-12-01

    Soil moisture (SM) in the root zone is a key factor governing water and energy fluxes at the land surface and its accurate knowledge is critical to predictions of weather and near-term climate, nutrient cycles, crop-yield, and ecosystem productivity. Microwave observations, such as those at L-band, are highly sensitive to soil moisture in the upper few centimeters (near-surface). The two satellite-based missions dedicated to soil moisture estimation include, the European Space Agency's Soil Moisture and Ocean Salinity (SMOS) mission and the planned NASA Soil Moisture Active/Passive (SMAP) [4] mission. The SMAP mission will include active and passive sensors at L-band to provide global observations of SM, with a repeat coverage of every 2-3 days. These observations can significantly improve root zone soil moisture estimates through data assimilation into land surface models (LSMs). Both the active (radar) and passive (radiometer) microwave sensors measure radiation quantities that are functions of soil dielectric constant and exhibit similar sensitivities to SM. In addition to the SM sensitivity, radar backscatter is highly sensitive to roughness of soil surface and scattering within the vegetation. These effects may produce a much larger dynamic range in backscatter than that produced due to SM changes alone. In this study, we discuss the field observations of active and passive signatures of growing corn at L-band from several seasons during the tenth Microwave, Water and Energy Balance Experiment (MicroWEX-10) conducted in North Central Florida, and to understand the sensitivity of these signatures to soil moisture under dynamic vegetation conditions. The MicroWEXs are a series of season-long field experiments conducted during the growing seasons of sweet corn, cotton, and energy cane over the past six years (for example, [22]). The corn was planted on July 5 and harvested on September 23, 2011 during MicroWEX-10. The size of the field was 0.04 km2 and the soils

  5. Irrigated acreage in the Bear River Basin as of the 1975 growing season. [Idaho, Utah, and Wyoming

    NASA Technical Reports Server (NTRS)

    Ridd, M. K.; Jaynes, R. A.; Landgraf, K. F.; Clark, L. D., Jr. (Principal Investigator)

    1982-01-01

    The irrigated cropland in the Bear River Basin as of the 1975 growing season was inventoried from satellite imagery. LANDSAT color infrared images (scale 1:125,000) were examined for early, mid, and late summer dates, and acreage was estimated by use of township/section overlays. The total basin acreage was estimated to be 573,435 acres, with individual state totals as follows: Idaho 234,370 acres; Utah 265,505 acres; and Wyoming 73,560 acres. As anticipated, wetland areas intermingled among cropland appears to have produced an over-estimation of irrigated acreage. According to a 2% random sample of test sites evaluated by personnel from the Soil Conservation Service such basin-wide over-estimation is 7.5%; individual counties deviate significantly from the basin-wide figure, depending on the relative amount of wetland areas intermingled with cropland.

  6. Long-term temporal changes in central European tree phenology (1946-2010) confirm the recent extension of growing seasons.

    PubMed

    Kolářová, Eva; Nekovář, Jiří; Adamík, Peter

    2014-10-01

    One of the ways to assess the impacts of climate change on plants is analysing their long-term phenological data. We studied phenological records of 18 common tree species and their 8 phenological phases, spanning 65 years (1946-2010) and covering the area of the Czech Republic. For each species and phenophase, we assessed the changes in its annual means (for detecting shifts in the timing of the event) and standard deviations (for detecting changes in duration of the phenophases). The prevailing pattern across tree species was that since around the year 1976, there has been a consistent advancement of the onset of spring phenophases (leaf unfolding and flowering) and subsequent acceleration of fruit ripening, and a delay of autumn phenophases (leaf colouring and leaf falling). The most considerable shifts in the timing of spring phenophases were displayed by early-successional short-lived tree species. The most pronounced temporal shifts were found for the beginning of seed ripening in conifers with an advancement in this phenophase of up to 2.2 days year⁻¹ in Scots Pine (Pinus sylvestris). With regards to the change in duration of the phenophases, no consistent patterns were revealed. The growing season has extended on average by 23.8 days during the last 35 years. The most considerable prolongation was found in Pedunculate Oak (Quercus robur): 31.6 days (1976-2010). Extended growing season lengths do have the potential to increase growth and seed productivity, but unequal shifts among species might alter competitive relationships within ecosystems.

  7. Contribution of grazing to soil atmosphere CH4 exchange during the growing season in a continental steppe

    NASA Astrophysics Data System (ADS)

    Tang, Shiming; Wang, Chengjie; Wilkes, Andreas; Zhou, Pei; Jiang, Yuanyuan; Han, Guodong; Zhao, Mengli; Huang, Ding; Schönbach, Philipp

    2013-03-01

    Degradation of steppes induced by overgrazing may affect the uptake of atmospheric methane (CH4) by soil sinks. However, uncertainty is associated with the very limited knowledge of gas fluxes in rapidly degrading steppe. In this study, we investigated the effects of grazing on CH4 uptake during the growing season in three types of steppe (meadow steppe, typical steppe and desert steppe and) in Inner Mongolia, China, to quantify and compare CH4 uptake in steppe ecosystems under different grazing management conditions. The CH4 fluxes were measured using an automatic cavity ring-down spectrophotometer at three steppe locations that differed primarily in grazing intensity. The results indicated that steppe soils were CH4 sinks throughout the growing season. CH4 uptake at all sites averaged 7.98 kg CH4-C ha-1 yr-1 (ranging from 1.53 to 18.74 kg CH4-C ha-1 yr-1), of which approximately 43.8% occurred in the desert steppe. CH4 uptake in the desert steppe increased 20.4% and 51.2% compared with the typical steppe and meadow steppe, respectively. Light grazing (LG) of steppe did not significantly change CH4 uptake compared with un-grazed (UG) steppe, but moderate and heavy grazing (MG, HG) reduced CH4 uptake significantly (by 6.8-37.9%, P < 0.05). These findings imply that reducing the grazing pressure on steppe would help increase the atmospheric CH4 sinks in steppe soils. Our results suggest that HG exerts a considerable negative impact on CH4 uptake in a continental steppe. Further studies involving year-round, intensive measurements of CH4 uptake are needed.

  8. Long-term temporal changes in central European tree phenology (1946-2010) confirm the recent extension of growing seasons

    NASA Astrophysics Data System (ADS)

    Kolářová, Eva; Nekovář, Jiří; Adamík, Peter

    2014-10-01

    One of the ways to assess the impacts of climate change on plants is analysing their long-term phenological data. We studied phenological records of 18 common tree species and their 8 phenological phases, spanning 65 years (1946-2010) and covering the area of the Czech Republic. For each species and phenophase, we assessed the changes in its annual means (for detecting shifts in the timing of the event) and standard deviations (for detecting changes in duration of the phenophases). The prevailing pattern across tree species was that since around the year 1976, there has been a consistent advancement of the onset of spring phenophases (leaf unfolding and flowering) and subsequent acceleration of fruit ripening, and a delay of autumn phenophases (leaf colouring and leaf falling). The most considerable shifts in the timing of spring phenophases were displayed by early-successional short-lived tree species. The most pronounced temporal shifts were found for the beginning of seed ripening in conifers with an advancement in this phenophase of up to 2.2 days year-1 in Scots Pine ( Pinus sylvestris). With regards to the change in duration of the phenophases, no consistent patterns were revealed. The growing season has extended on average by 23.8 days during the last 35 years. The most considerable prolongation was found in Pedunculate Oak ( Quercus robur): 31.6 days (1976-2010). Extended growing season lengths do have the potential to increase growth and seed productivity, but unequal shifts among species might alter competitive relationships within ecosystems.

  9. Communities of arbuscular mycorrhizal fungi detected in forest soil are spatially heterogeneous but do not vary throughout the growing season.

    PubMed

    Davison, John; Öpik, Maarja; Zobel, Martin; Vasar, Martti; Metsis, Madis; Moora, Mari

    2012-01-01

    Despite the important ecosystem role played by arbuscular mycorrhizal fungi (AMF), little is known about spatial and temporal variation in soil AMF communities. We used pyrosequencing to characterise AMF communities in soil samples (n = 44) from a natural forest ecosystem. Fungal taxa were identified by BLAST matching of reads against the MaarjAM database of AMF SSU rRNA gene diversity. Sub-sampling within our dataset and experimental shortening of a set of long reads indicated that our approaches to taxonomic identification and diversity analysis were robust to variations in pyrosequencing read length and numbers of reads per sample. Different forest plots (each 10 × 10 m and separated from one another by 30 m) contained significantly different soil AMF communities, and the pairwise similarity of communities decreased with distance up to 50 m. However, there were no significant changes in community composition between different time points in the growing season (May-September). Spatial structure in soil AMF communities may be related to the heterogeneous vegetation of the natural forest study system, while the temporal stability of communities suggests that AMF in soil represent a fairly constant local species pool from which mycorrhizae form and disband during the season.

  10. Downscaling 250-m MODIS growing season NDVI based on multiple-date landsat images and data mining approaches

    USGS Publications Warehouse

    Gu, Yingxin; Wylie, Bruce K.

    2015-01-01

    The satellite-derived growing season time-integrated Normalized Difference Vegetation Index (GSN) has been used as a proxy for vegetation biomass productivity. The 250-m GSN data estimated from the Moderate Resolution Imaging Spectroradiometer (MODIS) sensors have been used for terrestrial ecosystem modeling and monitoring. High temporal resolution with a wide range of wavelengths make the MODIS land surface products robust and reliable. The long-term 30-m Landsat data provide spatial detailed information for characterizing human-scale processes and have been used for land cover and land change studies. The main goal of this study is to combine 250-m MODIS GSN and 30-m Landsat observations to generate a quality-improved high spatial resolution (30-m) GSN database. A rule-based piecewise regression GSN model based on MODIS and Landsat data was developed. Results show a strong correlation between predicted GSN and actual GSN (r = 0.97, average error = 0.026). The most important Landsat variables in the GSN model are Normalized Difference Vegetation Indices (NDVIs) in May and August. The derived MODIS-Landsat-based 30-m GSN map provides biophysical information for moderate-scale ecological features. This multiple sensor study retains the detailed seasonal dynamic information captured by MODIS and leverages the high-resolution information from Landsat, which will be useful for regional ecosystem studies.

  11. Physiological and morphological responses of olive plants to ozone exposure during a growing season.

    PubMed

    Minnocci, Antonio; Panicucci, Alberto; Sebastiani, Luca; Lorenzini, Giacomo; Vitagliano, Claudio

    1999-05-01

    We studied physiological (gas exchange and stomatal aperture) and morphological (individual leaf area and stomatal density) responses in leaves of five-year-old olive plants (Olea europaea L. cvs. Frantoio and Moraiolo) exposed to filtered air containing < 3 ppb O(3) or 100 ppb O(3) for 5 h day(-1) for 120 days in fumigation chambers. After 100 days of treatment, leaf drop and development of necrotic spots were observed in O(3)-fumigated plants of Moraiolo but not of Frantoio. Significant reductions in photosynthetic activity (57%) and stomatal conductance (69%) were detected in O(3)-fumigated plants of Frantoio compared with control plants. In O(3)-fumigated plants of Moraiolo, the decrease in photosynthetic activity (17%) was not statistically significant, but a significant reduction in stomatal conductance (40%) was observed. In both cultivars, leaves that developed after exposure to O(3) showed decreased stomatal aperture (63.6 and 54.8% with respect to the Frantoio and Moraiolo controls, respectively) and one-sided leaf area, and increased stomatal density compared with control leaves. Actual transpiring stomatal surface decreased substantially in both Frantoio (59.8%) and Moraiolo (56.3%) in response to O(3) treatment. Relative transpiring stomatal surface (RTSS) in Frantoio decreased from 0.54 (control) to 0.27% (O(3) treated) of total leaf surface. The corresponding values for Moraiolo were 0.79 and 0.42%. However, because the RTSS of Moraiolo leaves in the O(3) treatment was 0.42 versus 0.27% in Frantoio, the potential uptake of O(3) was higher for Moraiolo plants than for Frantoio plants. The large O(3)-induced reduction in transpiring stomatal surface in both cultivars could have significant effects on olive productivity in the Mediterranean area, where high O(3) concentrations persist for long periods during the year. PMID:12651561

  12. Radionuclide concentrations in vegetation at radioactive-waste disposal Area G during the 1994 growing season

    SciTech Connect

    Fresquez, P.R.; Biggs, J.B.; Bennett, K.D.

    1995-07-01

    Overstory (pinon pine) and understory (grass and forb) vegetation samples were collected within and around selected points at Area G-a low-level radioactive solid-waste disposal facility at Los Alamos National Laboratory-for the analysis of tritium ({sup 3}H), strontium ({sup 90}Sr), plutonium ({sup 238} Pu and {sup 239}Pu), cesium ({sup 137}Cs), americium ({sup 241}Am), and total uranium. In general, most vegetation samples collected within and around Area G contained radionuclide levels in higher concentrations than vegetation collected from background areas. Tritium, in particular, was detected as high as 5,800 pCi/mL in overstory vegetation collected outside the fence just west of the tritium shafts; this suggests that tritium is migrating from this waste repository through subsurface pathways. Also, understory vegetation collected north of the transuranic (TRU) pads (outside the fence of Area G) contained the highest values of {sup 90}Sr, {sup 238}Pu, {sup 239}Pu, {sup 137}Cs, and {sup 241}Am, and may be a result of surface holding, storage, or disposal activities.

  13. Compositional equivalence of insect-protected glyphosate-tolerant soybean MON 87701 × MON 89788 to conventional soybean extends across different world regions and multiple growing seasons.

    PubMed

    Berman, Kristina H; Harrigan, George G; Nemeth, Margaret A; Oliveira, Wladecir S; Berger, Geraldo U; Tagliaferro, Fabio S

    2011-11-01

    The soybean product MON 87701 × MON 89788 expresses both the cry1Ac gene derived from Bacillus thuringiensis and the cp4 epsps (5-enolpyruvylshikimate-3-phosphate synthase) gene derived from Agrobacterium sp. strain CP4. Each biotechnology-derived trait confers specific benefits of insect resistance and glyphosate tolerance, respectively. The purpose of this study was to compare the composition of seed and forage from this combined-trait product to those of conventional soybean grown in geographically and climatically distinct regions. Field trials were conducted in the United States during the 2007 growing season, in Argentina during the 2007-2008 growing season, and in the northern and southern soybean regions of Brazil during the 2007-2008 and 2008-2009 growing seasons. Results demonstrated that the compositional equivalence of MON 87701 × MON 89788 to the conventional soybean extended across all regions and growing seasons. Further evaluation of the data showed that natural variation (region and growing season) contributed more to compositional variability in soybean, particularly for such components as isoflavones, fatty acids, and vitamin E, than transgene insertion.

  14. Evaluation of growth potential of Crimean juniper (Juniperus excelsa Bieb.) seedlings for the first growing season under Tekir forest nursery conditions in Kahramanmaras, Turkey.

    PubMed

    Avsar, Mahmut D; Tonguc, Fatih

    2003-04-01

    In this study, growth potential of Crimean juniper (Juniperus excelsa Bieb.) seedlings for the first growing season under Tekir Forest Nursery conditions in Kahramanmaras was evaluated. The height growth of Crimean juniper seedlings was relatively close to that of Lebanon cedar (Cedrus libani A. Rich.) seedlings produced in the same nursery, but their root collar diameters were fairly lower than that of Lebanon cedar seedlings. According to coniferous seedling standards of Turkish Standards Institute, the height growth of Crimean juniper seedlings was fairly good, but their root collar diameters were slightly small. In this respect, that 2+0 or 1+1 Crimean juniper seedlings are used in reforestation activities in the region would be more useful than 1+0 seedlings.

  15. Nitrous oxide emissions from a maize field during two consecutive growing seasons in the north China plain.

    PubMed

    Zhang, Yuanyuan; Liu, Junfeng; Mu, Yujing; Xu, Zhu; Pei, Shuwei; Lun, Xiaoxiu; Zhang, Ying

    2012-01-01

    Nitrous oxide (N2O) emissions from a maize field in the North China Plain (Wangdu County, Hebei Province, China) were investigated using static chambers during two consecutive maize growing seasons in the 2008 and 2009. The N2O pulse emissions occurred with duration of about 10 days after basal and additional fertilizer applications in the both years. The average N20 fluxes from the CK (control plot, without crop, fertilization and irrigation), NP (chemical N fertilizer), SN (wheat straw returning plus chemical N fertilizer), OM-1/2N (chicken manure plus half chemical N fertilizer) and OMN (chicken manure plus chemical N fertilizer) plots in 2008 were 8.51, 72.1, 76.6, 101, 107 ng N/(m2 x sec), respectively, and in 2009 were 33.7, 30.0 and 35.0 ng N/(m2 x sec) from CK, NP and SN plots, respectively. The emission factors of the applied fertilizer as N20-N (EFs) were 3.8% (2008) and 1.1% (2009) for the NP plot, 3.2% (2008) and 1.2% (2009) for the SN plot, and 2.8% and 2.2% in 2008 for the OM-1/2N and OMN plots, respectively. Hydromorphic properties of the investigated soil (with gley) are in favor of denitrification. The large differences of the soil temperature and water-filled pore space (WFPS) between the two maize seasons were suspected to be responsible for the significant yearly variations. Compared with the treatments of NP and SN, chicken manure coupled with compound fertilizer application significantly reduced fertilizer loss rate as N2O-N. PMID:22783628

  16. Steers grazing blue grama rangeland throughout the growing season. I. Dietary composition, intake, digesta kinetics and ruminal fermentation.

    PubMed

    Funk, M A; Galyean, M L; Branine, M E; Krysl, L J

    1987-11-01

    Four sampling periods on blue grama rangeland in northeastern New Mexico evaluated effects of advancing forage maturity and drought-induced dormancy on dietary nutrient and botanical composition, intake, digesta kinetics and ruminal fermentation in grazing beef steers. Six ruminally cannulated and three esophageally cannulated steers freely grazed a 12-ha pasture during the study. Sampling periods lasted 11 d and started June 2, during the early growing season (EGS); June 22, during early summer dormancy (ESD); July 21, during late summer dormancy (LSD); and August 25, 1985, during the late growing season (LGS). Forage availability was not limiting in any sampling period. Steers consumed a greater (P less than .05) percentage in forbs and lower percentage of grasses in EGS and ESD than in LSD and LGS. Dietary in vitro organic matter digestibility was lower (P less than .05) in ESD than in EGS, LSD and LGS. Dietary N content was higher (P less than .05) in EGs and LGS than in ESD and LSD. Neutral detergent fiber content was lower (P less than .05) in EGS than in other sampling periods, while dietary lignin contents were similar for all sampling periods. Voluntary organic matter intake was similar for all sampling periods; however, estimated gastrointestinal tract fill was greater (P less than .05) in ESD and LSD than in EGS and LGS. Particulate passage rate was slower (P less than .05) and total mean retention time longer (P less than .05) in LSD than in other sampling periods. Rate and lag time of neutral detergent fiber digestion were not different among sampling periods. Ruminal pH was greater (P less than .05) at 3 and 6 h after sunrise in ESD than in other sampling periods. Ruminal ammonia concentrations were lower (P less than .05) in ESD and LSD than in EGS and LGS at 3 and 6 h after sunrise. Total volatile fatty acid concentrations were lower (P less than .05) in ESD than in EGS and LSD at 3 h after sunrise and lower (P less than .10) than EGS and LGS at 9 h

  17. Importance of recent shifts in soil thermal dynamics on growing season length, productivity, and carbon sequestration in terrestrial high-latitude ecosystems

    USGS Publications Warehouse

    Euskirchen, E.S.; McGuire, A.D.; Kicklighter, D.W.; Zhuang, Q.; Clein, J.S.; Dargaville, R.J.; Dye, D.G.; Kimball, J.S.; McDonald, K.C.; Melillo, J.M.; Romanovsky, V.E.; Smith, N.V.

    2006-01-01

    In terrestrial high-latitude regions, observations indicate recent changes in snow cover, permafrost, and soil freeze-thaw transitions due to climate change. These modifications may result in temporal shifts in the growing season and the associated rates of terrestrial productivity. Changes in productivity will influence the ability of these ecosystems to sequester atmospheric CO2. We use the terrestrial ecosystem model (TEM), which simulates the soil thermal regime, in addition to terrestrial carbon (C), nitrogen and water dynamics, to explore these issues over the years 1960-2100 in extratropical regions (30-90??N). Our model simulations show decreases in snow cover and permafrost stability from 1960 to 2100. Decreases in snow cover agree well with National Oceanic and Atmospheric Administration satellite observations collected between the years 1972 and 2000, with Pearson rank correlation coefficients between 0.58 and 0.65. Model analyses also indicate a trend towards an earlier thaw date of frozen soils and the onset of the growing season in the spring by approximately 2-4 days from 1988 to 2000. Between 1988 and 2000, satellite records yield a slightly stronger trend in thaw and the onset of the growing season, averaging between 5 and 8 days earlier. In both, the TEM simulations and satellite records, trends in day of freeze in the autumn are weaker, such that overall increases in growing season length are due primarily to earlier thaw. Although regions with the longest snow cover duration displayed the greatest increase in growing season length, these regions maintained smaller increases in productivity and heterotrophic respiration than those regions with shorter duration of snow cover and less of an increase in growing season length. Concurrent with increases in growing season length, we found a reduction in soil C and increases in vegetation C, with greatest losses of soil C occurring in those areas with more vegetation, but simulations also suggest that

  18. Learning Activities for the Growth Season.

    ERIC Educational Resources Information Center

    Darby, Linda, Ed.

    This poster, illustrated with a graphic of a caterpillar changing to a cocoon and emerging as a butterfly, presents learning activities for 7 weeks based on the seven stages of growth in the President's "Call to Action." Each week includes 5 days of activities based on seven themes: (1) "Reading on Your Own"; (2) "Getting Ready for Algebra"; (3)…

  19. Daily and seasonal activity patterns in blackheaded munia.

    PubMed

    GuptA, Neelu Jain

    2014-05-01

    To test the circadian clock characteristics, activity behaviour of male blackheaded munia was recorded. Two experiments were performed. In experiment 1A, activity of munia was recorded under long days, LD (14L: 10D); and short days, SD (10L: 14D). Locomotor activity of two groups of munia exposed to equinox (12L: 12D) daylength followed by transfer of one group each to continuous dimlight (DD) and continuous bright light (LL) was recorded in experiment 1B. Experiment 2 aimed to describe seasonal trend in daily pattern of activity/rest cycle under natural illumination conditions (NDL). Hourly activity during daytime was more under SD than under LD. Munia did not exhibit bimodality in daily activity pattern; activity during morning, M (2h) was more than evening, E. A free-running activity rhythm was recorded in munia under DD; the same was arrhythmic under LL. The seasonal pattern in daily activity profiles under NDL corresponds to the seasonal changes in daylength. Daylength regulates daily and seasonal activity patterns in blackheaded munia. PMID:24851413

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

    PubMed

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

    2014-01-01

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

  1. Phenological and water-use patterns underlying maximum growing season length at the highest elevations: implications under climate change.

    PubMed

    Linares, Juan Carlos; Covelo, Felisa; Carreira, José Antonio; Merino, José Ángel

    2012-02-01

    Consequences of climate change on tree phenology are readily observable, but little is known about the variations in phenological sensitivity to drought between populations within a species. In this study, we compare the phenological sensitivity to temperature and water availability in Abies pinsapo Boiss., a drought-sensitive Mediterranean fir, across its altitudinal distribution gradient. Twig growth and needle fall were related to temperature, precipitation and plant water status on a daily scale. Stands located at the top edge of the distributional range showed the most favourable water balance, maximum growth rates and little summer defoliation. Towards higher elevations, the observed delay in budburst date due to lower spring temperatures was overcome by a stronger delay in growth cessation date due to the later onset of strong water-deficit conditions in the summer. This explains an extended growing season and the greatest mean growth at the highest elevation. Conversely, lower predawn xylem water potentials and early partial stomatal closure and growth cessation were found in low-elevation A. pinsapo trees. An earlier and higher summer peak of A. pinsapo litterfall was also observed at these water-limited sites. Our results illustrate the ecophysiological background of the ongoing altitudinal shifts reported for this relict tree species under current climatic conditions.

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

    PubMed Central

    Li, Yunzhao; Du, Siyao; Han, Guangxuan; Xing, Qinghui; Wu, Huifeng; Wang, Guangmei

    2014-01-01

    The ecological problems caused by dry and wet deposition of atmospheric nitrogen have been widespread concern in the world. In this study, wet and dry atmospheric depositions were monitored in plant growing season in the coastal zone of the Yellow River Delta (YRD) using automatic sampling equipment. The results showed that SO42− and Na+ were the predominant anion and cation, respectively, in both wet and dry atmospheric depositions. The total atmospheric nitrogen deposition was ~2264.24 mg m−2, in which dry atmospheric nitrogen deposition was about 32.02%. The highest values of dry and wet atmospheric nitrogen deposition appeared in May and August, respectively. In the studied area, NO3−–N was the main nitrogen form in dry deposition, while the predominant nitrogen in wet atmospheric deposition was NH4+–N with ~56.51% of total wet atmospheric nitrogen deposition. The average monthly attribution rate of atmospheric deposition of NO3−–N and NH4+–N was ~31.38% and ~20.50% for the contents of NO3−–N and NH4+–N in 0–10 cm soil layer, respectively, suggested that the atmospheric nitrogen was one of main sources for soil nitrogen in coastal zone of the YRD. PMID:24977238

  3. Wavelength shifts in fluorescence maxima of stressed and non-stressed Norway spruce needles over the growing season

    NASA Technical Reports Server (NTRS)

    Banninger, Cliff; Chappelle, E.

    1991-01-01

    Laboratory fluorescence measurements of first and third year metal stressed and non stressed Norway spruce needles collected in May, Jul. Sep. and Nov. display significant wavelength shifts in the intensity maxima in the blue, green, red, and near infrared spectral regions, with the largest shifts occurring in the blue spectral region for both first and third year needles from Nov. Smaller, but the otherwise significant shifts also take place in the blue spectral region for first year needles from Sep. in the red spectral region for third year neddles from May, Jul. and Sep. and in the near infrared spectral region for first and third year needles from Jul. and Sep. Wavelength shifts in needle fluorescence maxima over the growing season are greatest in the blue and to a lesser extent, greenspectral regions from Sep. to Nov. but are also significant in the red and near infrared spectral regions from Jul. to Sep. and Sep. to Nov., and in the near infrared spectral region also from May to Jul.

  4. Utilisation of young and old soil carbon sources by microbial groups differ during the growing season and between experimental treatments in a long-term field experiment

    NASA Astrophysics Data System (ADS)

    Börjesson, Gunnar; Menichetti, Lorenzo; Thornton, Barry; Campbell, Colin; Kätterer, Thomas

    2014-05-01

    Soil organic matter (SOM)is the largest active carbon pool in the terrestrial environment. SOM is a key factor for soil fertility, but is also important for the sequestration of atmospheric CO2. In agricultural soils, management of plant residues and the use of organic fertilisers play important roles for maintaining SOM. Switching from C3 plants to C4 plants such as maize, enables a natural labelling in situ; when coupled with compound specific 13C isotope analysis of phospholipid fatty acids (PLFAs) it allows the proportion of new C (fixed after the switch added to soil from above- and belowground litter and root exudates) and the proportion of old C (fixed prior to the switch derived from turnover of organic matter) utilised by the soil microbial community to be determined. (new paragraph) A field experiment in Sweden, amended with different mineral and organic fertilisers since 1956, was grown with C3 plants, mainly cereals until 1999. From the year 2000 silage maize was grown every year. In 2012, soil from four replicate plots of five experimental treatments, N fertilised, N fertilised amended with straw and sewage sludge, and two controls (bare fallow and cropped unfertilised) were sampled three times, at the start, middle and end of the growing season. Phospholipid fatty acids (PLFAs) were extracted from all soil samples and analysed for concentrations and 13C content. (new paragraph) Total PLFA concentrations and also the PLFA/SOM ratios increased with SOM in the different treatments. Seasonal variation in total PLFA was small except for the most SOM-rich treatment (sewage sludge) where concentrations significantly decreased during the growing season indicating the depletion of a labile SOM pool. Weighted mean values of δ13C in PLFAs show that the plots fertilised with only calcium nitrate had the highest δ13C-values in PLFAs before (-20.24 o) and after the vegetation period (-20.37 o), due to a large input of 13C-enriched plant material. However, during

  5. Climate change trade-offs in the side-blotched lizard (Uta stansburiana): effects of growing-season length and mild temperatures on winter survival.

    PubMed

    Zani, Peter A

    2008-01-01

    An expanding body of literature has demonstrated that global climate change continues to adversely affect many populations, species, and ecosystems. However, life-history theory also predicts possible benefits from longer growing seasons and less severe winters, particularly for ectotherms. To test the idea that climate change will have benefits as well as costs, I studied the impacts of growing-season length on growth and overwintering conditions on survival time using side-blotched lizards (Uta stansburiana). Experiments in replicate field enclosures revealed that fall growing-season length has a direct effect on overwintering body size. Laboratory experiments revealed that both size and overwintering temperature have direct effects on winter survival time. Larger lizards are more likely to survive longer regardless of winter temperature. Furthermore, animals in colder (but still mild) winter microenvironments are more likely to survive longer than those in warmer winter environments. These results indicate that warmer winters caused by global climate change have the potential to negatively affect ectotherm populations. However, longer growing seasons may offset losses by allowing additional growth and energy storage. Thus, environmental alterations associated with climate change may be simultaneously beneficial and detrimental, and the long-term persistence of certain organisms may depend on the relative strength of their effects.

  6. Field evaluation of green and red leaf lettuce cultivars in the Imperial, San Joaquin, and Salinas Valleys of California for heat tolerance and extension of the growing seasons

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Global warming poses serious threats and challenges to the production of leafy vegetables. Being a cool-season crop, lettuce is vulnerable to heat-stress. To adapt to climate change, this study was conducted to evaluate the performance of leaf lettuce genotypes for heat tolerance by growing them in ...

  7. N2O and CH4 emissions from a Chinese wheat-rice cropping system under different tillage practices during the wheat-growing season

    NASA Astrophysics Data System (ADS)

    Zhang, Y.

    2015-12-01

    The annual wheat (Triticum aestivum L.)-rice (Oryza sativa L.) cropping system is the most important cereal production system in the Yangtze River Valley of China, in which various tillage systems are currently implemented during the wheat-growing season. The emissions of nitrous oxide (N2O) and methane (CH4) from the different tillage systems in this system remain unclear. We conducted a 3-year field experiment in a wheat-rice cropping system in a silt clay loam soil to investigate the effects of the type of tillage employed during the wheat-growing season (no-tillage (NT), reduced tillage (RT) or conventional tillage (CT)) on the emissions of N2O and CH4 using the static chamber method over three annual rotation cycles from the 2008 wheat season to the 2011 rice season. The results revealed that the adoption of an NT system during the wheat-growing season significantly increased CH4 emissions during both the wheat-growing season and the following rice-growing season. Over the three annual rotation cycles studied, the annual N2O emissions from the NT (2.24 kg N2O-N ha-1) and CT (2.01 kg N2O-N ha-1) treatments were similar to each other and significantly higher than those from the RT treatment (1.73 kg N2O-N ha-1); the annual CH4 emissions were significantly higher from the NT (100.1 kg CH4-C ha-1) than the CT (83.7 kg CH4-C ha-1) and RT (73.9 kg CH4-C ha-1) systems. The overall results regarding the net global warming potential associated with annual N2O and CH4 emissions indicate that the conversion of conventional tillage to no-tillage systems during the wheat-growing season would intensify the radiative forcing in wheat-rice cropping systems in China.

  8. Phenology Shifts at Start vs. End of Growing Season in Temperate Vegetation Over the Northern Hemisphere for the Period 1982-2008

    NASA Technical Reports Server (NTRS)

    Jeong, Su-Jong; Ho, Chang-Hoi; Gim, Hyeon-Ju; Brown, Molley E.

    2011-01-01

    Changes in vegetative growing seasons are dominant indicators of the dynamic response of ecosystems to climate change. Therefore, knowledge of growing seasons over the past decades is essential to predict ecosystem changes. In this study, the long-term changes in the growing seasons of temperate vegetation over the Northern Hemisphere were examined by analyzing satellite-measured normalized difference vegetation index and reanalysis temperature during 1982 2008. Results showed that the length of the growing season (LOS) increased over the analysis period; however, the role of changes at the start of the growing season (SOS) and at the end of the growing season (EOS) differed depending on the time period. On a hemispheric scale, SOS advanced by 5.2 days in the early period (1982-1999) but advanced by only 0.2 days in the later period (2000-2008). EOS was delayed by 4.3 days in the early period, and it was further delayed by another 2.3 days in the later period. The difference between SOS and EOS in the later period was due to less warming during the preseason (January-April) before SOS compared with the magnitude of warming in the preseason (June September) before EOS. At a regional scale, delayed EOS in later periods was shown. In North America, EOS was delayed by 8.1 days in the early period and delayed by another 1.3 days in the later period. In Europe, the delayed EOS by 8.2 days was more significant than the advanced SOS by 3.2 days in the later period. However, in East Asia, the overall increase in LOS during the early period was weakened in the later period. Admitting regional heterogeneity, changes in hemispheric features suggest that the longer-lasting vegetation growth in recent decades can be attributed to extended leaf senescence in autumn rather than earlier spring leaf-out. Keywords: climate change, growing season, NDVI (normalized difference vegetation index), Northern Hemisphere, phenology,

  9. Effect of soil frost on growing season nitrogen uptake by fine roots of mature trees in northern hardwood forests of the United States

    NASA Astrophysics Data System (ADS)

    Socci, A. M.; Templer, P. H.

    2010-12-01

    Forests of the northeastern United States are predicted to experience a decrease in the depth and duration of the winter snowpack over the next 100 years. Even when coupled with warmer winter air temperatures, the absence of snow as insulation can increase soil frost during the winter months. Past research has determined that there are species-level effects of soil frost on dominant forest trees. For example, in stands dominated by sugar maple (Acer saccharum), induced soil frost led to increased fine root mortality and soil nitrate leaching. Soil frost also increased fine root mortality in stands dominated by yellow birch (Betula allegheniensis), but there was no significant change in leaching of soil nitrate. We hypothesized that greater nitrogen (N) losses from stands dominated by sugar maple may be due to reduced N uptake by fine roots of this tree species. To determine the impact of increased soil freezing on fine root uptake of N, we established a snow manipulation experiment in mixed sugar maple/American beech (Fagus grandifolia) forests at the Hubbard Brook Experimental Forest in New Hampshire (n=4 paired snow-removal and reference plots; each 13m X 13m). Snow removal occurred during the first six weeks of winter over two years. During each growing season following snow removal, we used the N depletion technique to measure in situ rates of uptake of ammonium and nitrate by fine roots of sugar maple during the early, peak and late growing season. Among all sampling dates and plots, we observed significantly lower uptake of N as nitrate compared to ammonium. During the first growing season, at moderate ammonium availability (35 μM N) we observed significantly less uptake of ammonium by fine roots of sugar maple in the snow removal plots relative to the reference plots during the early growing season (April-May), with no significant differences in uptake of ammonium during the peak (July) and late (September) growing season. We observed no differences in

  10. Impacts of Short-Rotation Early-Growing Season Prescribed Fire on a Ground Nesting Bird in the Central Hardwoods Region of North America.

    PubMed

    Pittman, H Tyler; Krementz, David G

    2016-01-01

    Landscape-scale short-rotation early-growing season prescribed fire, hereafter prescribed fire, in upland hardwood forests represents a recent shift in management strategies across eastern upland forests. Not only does this strategy depart from dormant season to growing season prescriptions, but the strategy also moves from stand-scale to landscape-scale implementation (>1,000 ha). This being so, agencies are making considerable commitments in terms of time and resources to this management strategy, but the effects on wildlife in upland forests, especially those dominated by hardwood canopy species, are relatively unknown. We initiated our study to assess whether this management strategy affects eastern wild turkey reproductive ecology on the Ozark-St. Francis National Forest. We marked 67 wild turkey hens with Global Positioning System (GPS) Platform Transmitting Terminals in 2012 and 2013 to document exposure to prescribed fire, and estimate daily nest survival, nest success, and nest-site selection. We estimated these reproductive parameters in forest units managed with prescribed fire (treated) and units absent of prescribed fire (untreated). Of 60 initial nest attempts monitored, none were destroyed or exposed to prescribed fire because a majority of fires occurred early than a majority of the nesting activity. We found nest success was greater in untreated units than treated units (36.4% versus 14.6%). We did not find any habitat characteristic differences between successful and unsuccessful nest-sites. We found that nest-site selection criteria differed between treated and untreated units. Visual concealment and woody ground cover were common selection criteria in both treated and untreated units. However, in treated units wild turkey selected nest-sites with fewer small shrubs (<5 cm ground diameter) and large trees (>20 cm DBH) but not in untreated units. In untreated units wild turkey selected nest-sites with more large shrubs (≥5 cm ground diameter

  11. Impacts of Short-Rotation Early-Growing Season Prescribed Fire on a Ground Nesting Bird in the Central Hardwoods Region of North America.

    PubMed

    Pittman, H Tyler; Krementz, David G

    2016-01-01

    Landscape-scale short-rotation early-growing season prescribed fire, hereafter prescribed fire, in upland hardwood forests represents a recent shift in management strategies across eastern upland forests. Not only does this strategy depart from dormant season to growing season prescriptions, but the strategy also moves from stand-scale to landscape-scale implementation (>1,000 ha). This being so, agencies are making considerable commitments in terms of time and resources to this management strategy, but the effects on wildlife in upland forests, especially those dominated by hardwood canopy species, are relatively unknown. We initiated our study to assess whether this management strategy affects eastern wild turkey reproductive ecology on the Ozark-St. Francis National Forest. We marked 67 wild turkey hens with Global Positioning System (GPS) Platform Transmitting Terminals in 2012 and 2013 to document exposure to prescribed fire, and estimate daily nest survival, nest success, and nest-site selection. We estimated these reproductive parameters in forest units managed with prescribed fire (treated) and units absent of prescribed fire (untreated). Of 60 initial nest attempts monitored, none were destroyed or exposed to prescribed fire because a majority of fires occurred early than a majority of the nesting activity. We found nest success was greater in untreated units than treated units (36.4% versus 14.6%). We did not find any habitat characteristic differences between successful and unsuccessful nest-sites. We found that nest-site selection criteria differed between treated and untreated units. Visual concealment and woody ground cover were common selection criteria in both treated and untreated units. However, in treated units wild turkey selected nest-sites with fewer small shrubs (<5 cm ground diameter) and large trees (>20 cm DBH) but not in untreated units. In untreated units wild turkey selected nest-sites with more large shrubs (≥5 cm ground diameter

  12. Impacts of Short-Rotation Early-Growing Season Prescribed Fire on a Ground Nesting Bird in the Central Hardwoods Region of North America

    PubMed Central

    2016-01-01

    Landscape-scale short-rotation early-growing season prescribed fire, hereafter prescribed fire, in upland hardwood forests represents a recent shift in management strategies across eastern upland forests. Not only does this strategy depart from dormant season to growing season prescriptions, but the strategy also moves from stand-scale to landscape-scale implementation (>1,000 ha). This being so, agencies are making considerable commitments in terms of time and resources to this management strategy, but the effects on wildlife in upland forests, especially those dominated by hardwood canopy species, are relatively unknown. We initiated our study to assess whether this management strategy affects eastern wild turkey reproductive ecology on the Ozark-St. Francis National Forest. We marked 67 wild turkey hens with Global Positioning System (GPS) Platform Transmitting Terminals in 2012 and 2013 to document exposure to prescribed fire, and estimate daily nest survival, nest success, and nest-site selection. We estimated these reproductive parameters in forest units managed with prescribed fire (treated) and units absent of prescribed fire (untreated). Of 60 initial nest attempts monitored, none were destroyed or exposed to prescribed fire because a majority of fires occurred early than a majority of the nesting activity. We found nest success was greater in untreated units than treated units (36.4% versus 14.6%). We did not find any habitat characteristic differences between successful and unsuccessful nest-sites. We found that nest-site selection criteria differed between treated and untreated units. Visual concealment and woody ground cover were common selection criteria in both treated and untreated units. However, in treated units wild turkey selected nest-sites with fewer small shrubs (<5 cm ground diameter) and large trees (>20 cm DBH) but not in untreated units. In untreated units wild turkey selected nest-sites with more large shrubs (≥5cm ground diameter) but

  13. Crop evapotranspiration-based irrigation management during the growing season in the arid region of northwestern China.

    PubMed

    Chang, Xuexiang; Zhao, Wenzhi; Zeng, Fanjiang

    2015-11-01

    In arid northwestern China, water shortages have triggered recent regulations affecting irrigation water use in desert-oasis agricultural systems. In order to determine the actual water demand of various crops and to develop standards for the rational use of water resources, we analyzed meteorological data from the Fukang desert ecosystem observation and experiment station (FKD), the Cele desert-grassland ecosystem observation and research station (CLD), and the Linze Inland River Basin Comprehensive Research Station (LZD), which all belong to the Chinese Ecosystem Research Network. We researched crop evapotranspiration (ETc) using the water balance method, the FAO-56 Penman-Monteith method, the Priestley-Taylor method, and the Hargreaves method, during the growing seasons of 2005 through 2009. Results indicate substantial differences in ETc, depending on the method used. At the CLD, the ETc from the soil water balance, FAO-56 Penman-Monteith, Priestley-Taylor, and Hargreaves methods were 1150.3±380.8, 783.7±33.6, 1018.3±22.1, and 611.2±23.3 mm, respectively; at the FKD, the corresponding results were 861.0±67.0, 834.2±83.9, 1453.5±47.1, and 1061.0±38.2 mm, respectively; and at the LZD, 823.4±110.4, 726.0±0.4, 722.3±29.4, and 1208.6±79.1 mm, respectively. The FAO-56 Penman-Monteith method provided a fairly good estimation of E Tc compared with the Priestley-Taylor and Hargreaves methods. PMID:26497559

  14. Crop evapotranspiration-based irrigation management during the growing season in the arid region of northwestern China.

    PubMed

    Chang, Xuexiang; Zhao, Wenzhi; Zeng, Fanjiang

    2015-11-01

    In arid northwestern China, water shortages have triggered recent regulations affecting irrigation water use in desert-oasis agricultural systems. In order to determine the actual water demand of various crops and to develop standards for the rational use of water resources, we analyzed meteorological data from the Fukang desert ecosystem observation and experiment station (FKD), the Cele desert-grassland ecosystem observation and research station (CLD), and the Linze Inland River Basin Comprehensive Research Station (LZD), which all belong to the Chinese Ecosystem Research Network. We researched crop evapotranspiration (ETc) using the water balance method, the FAO-56 Penman-Monteith method, the Priestley-Taylor method, and the Hargreaves method, during the growing seasons of 2005 through 2009. Results indicate substantial differences in ETc, depending on the method used. At the CLD, the ETc from the soil water balance, FAO-56 Penman-Monteith, Priestley-Taylor, and Hargreaves methods were 1150.3±380.8, 783.7±33.6, 1018.3±22.1, and 611.2±23.3 mm, respectively; at the FKD, the corresponding results were 861.0±67.0, 834.2±83.9, 1453.5±47.1, and 1061.0±38.2 mm, respectively; and at the LZD, 823.4±110.4, 726.0±0.4, 722.3±29.4, and 1208.6±79.1 mm, respectively. The FAO-56 Penman-Monteith method provided a fairly good estimation of E Tc compared with the Priestley-Taylor and Hargreaves methods.

  15. Variations in bacterial communities during foliar litter decomposition in the winter and growing seasons in an alpine forest of the eastern Tibetan Plateau.

    PubMed

    Zhao, Yeyi; Wu, Fuzhong; Yang, Wanqin; Tan, Bo; He, Wei

    2016-01-01

    Bacterial communities are the primary engineers during litter decomposition and related material cycling, and they can be strongly controlled by seasonal changes in temperature and other environmental factors. However, limited information is available on changes in the bacterial community from winter to the growing season as litter decomposition proceeds in cold climates. Here, we investigated the abundance and structure of bacterial communities using real-time quantitative PCR and denaturing gradient gel electrophoresis (DGGE) during a 2-year field study of the decomposition of litter of 4 species in the winter and growing seasons of an alpine forest of the eastern Tibetan Plateau. The abundance of the bacterial 16S rRNA gene was relatively high during decomposition of cypress and birch litter in the first winter, but for the other litters 16S rRNA abundance during both winters was significantly lower than during the following growing season. A large number of bands were observed on the DGGE gels, and their intensities and number from the winter samples were lower than those from the growing season during the 2-year decomposition experiment. Eighty-nine sequences from the bands of bacteria that had been cut from the DGGE gels were affiliated with 10 distinct classes of bacteria and an unknown group. A redundancy analysis indicated that the moisture, mass loss, and elemental content (e.g., C, N, and P) of the litter significantly affected the bacterial communities. Collectively, the results suggest that uneven seasonal changes in climate regulate bacterial communities and other decomposers, thus affecting their contribution to litter decomposition processes in the alpine forest.

  16. Growing seasons of Nordic mountain birch in northernmost Europe as indicated by long-term field studies and analyses of satellite images.

    PubMed

    Shutova, E; Wielgolaski, F E; Karlsen, S R; Makarova, O; Berlina, N; Filimonova, T; Haraldsson, E; Aspholm, P E; Flø, L; Høgda, K A

    2006-11-01

    The phenophases first greening (bud burst) and yellowing of Nordic mountain birch (Betula pubescens ssp.tortuosa, also called B. p. ssp. czerepanovii) were observed at three sites on the Kola Peninsula in northernmost Europe during the period 1964-2003, and at two sites in the trans-boundary Pasvik-Enare region during 1994-2003. The field observations were compared with satellite images based on the GIMMS-NDVI dataset covering 1982-2002 at the start and end of the growing season. A trend for a delay of first greening was observed at only one of the sites (Kandalaksha) over the 40 year period. This fits well with the delayed onset of the growing season for that site based on satellite images. No significant changes in time of greening at the other sites were found with either field observations or satellite analyses throughout the study period. These results differ from the earlier spring generally observed in other parts of Europe in recent decades. In the coldest regions of Europe, e.g. in northern high mountains and the northernmost continental areas, increased precipitation associated with the generally positive North Atlantic Oscillation in the last few decades has often fallen as snow. Increased snow may delay the time of onset of the growing season, although increased temperature generally causes earlier spring phenophases. Autumn yellowing of birch leaves tends towards an earlier date at all sites. Due to both later birch greening and earlier yellowing at the Kandalaksha site, the growing season there has also become significantly shorter during the years observed. The sites showing the most advanced yellowing in the field throughout the study period fit well with areas showing an earlier end of the growing season from satellite images covering 1982-2002. The earlier yellowing is highly correlated with a trend at the sites in autumn for earlier decreasing air temperature over the study period, indicating that this environmental factor is important also for

  17. The warming-induced increase of growing-season freezing event and its effect on the survival and growth of treeline seedlings in the Sergyemla Mountains, Southeast Tibet

    NASA Astrophysics Data System (ADS)

    Shen, W.; Zhang, L.; Liu, X.; Luo, T.

    2013-12-01

    Seedling establishment is important to the formation and dynamics of alpine treeline. How can we understand the limitation to the survival and growth of seedlings at and above treeline under a warmer climate? In this study, we conducted a 4-yr reciprocal transplant experiment of seed-based fir and root-sprouting juniper seedlings on opposite slopes of a valley in the Sergyemla Mountains, where annual mean air-temperature differed by 0.5-2.1 K and annual precipitation was similar. We aim to test the hypotheses that the warmer climate on the south-facing slope generally has more severe growing-season freezing events, and the seed-based fir seedlings are especially vulnerable to the warming-induced increase of freezing days in the early growing season. The frequency, intensity and duration of the growing-season freezing events across site habitats generally increased from north- to south-facing slopes. The freezing days in the early growing season (April-June) were mainly determined by daily minimum net radiation and relative humidity, and positively correlated with annual mean air-temperature across sites and years. The survival rates of transplanted fir seedlings on the south-facing slope greatly decreased by <60% in forested habitat and by <40% in non-forested habitat, while their survival rates on the north-facing slope did not change in forested habitat and slowly decreased by 85% in non-forested habitat. The survival rates of transplanted juniper seedlings decreased by 68%-84% with unclear change trends among different slopes and habitats. In pooled data across sites and years, annual top-shoot growth rates decreased in fir seedlings but varied little in juniper seedlings with increasing freezing days in the early growing season. The data supported our hypotheses. The warming-enhanced difficulty of seedling establishment above treeline can explain why the fir treeline position did not advance with climatic warming in past 200 years.

  18. Regulation of Seasonal Reproduction by Hypothalamic Activation of Thyroid Hormone

    PubMed Central

    Shinomiya, Ai; Shimmura, Tsuyoshi; Nishiwaki-Ohkawa, Taeko; Yoshimura, Takashi

    2014-01-01

    Organisms living outside the tropics measure the changes in the length of the day to adapt to seasonal changes in the environment. Animals that breed during spring and summer are called long-day breeders, while those that breed during fall are called short-day breeders. Although the influence of thyroid hormone in the regulation of seasonal reproduction has been known for several decades, its precise mechanism remained unknown. Recent studies revealed that the activation of thyroid hormone within the mediobasal hypothalamus plays a key role in this phenomenon. This localized activation of the thyroid hormone is controlled by thyrotropin (thyroid-stimulating hormone) secreted from the pars tuberalis of the pituitary gland. Although seasonal reproduction is a rate-limiting factor in animal production, genes involved in photoperiodic signal transduction pathway could emerge as potential targets to facilitate domestication. PMID:24600435

  19. Teaching Writing. Three Seasonal Activities to Hone Kids' Observation Skills.

    ERIC Educational Resources Information Center

    Power, Brenda

    1997-01-01

    The seasonal activities presented are: observing herbs to encourage use of the senses in writing; watching a jack-o'-lantern wither to learn skills in writing details; and building snowmen to learn to explain a string of events in writing. (SM)

  20. Investigating seasonal gravity wave activity in the summer polar mesosphere

    NASA Astrophysics Data System (ADS)

    Zhao, Y.; Taylor, M. J.; Randall, C. E.; Lumpe, J. D.; Siskind, D. E.; Bailey, S. M.; Russell, J. M.

    2015-05-01

    The NASA Aeronomy of Ice in the Mesosphere (AIM) satellite is the first spaceborne mission dedicated to studying high-altitude (~83 km) Polar Mesospheric Clouds (PMCs). Since its launch in 2007, the Cloud Imaging and Particle Size (CIPS) instrument onboard AIM has obtained large-field, high resolution (25 km2/pixel) images of the PMCs, enabling a unique investigation of mesospheric gravity wave activity in the summer polar mesosphere where previous measurements have been sparse. In this study, we have analyzed 12 consecutive seasons of AIM/CIPS PMC albedo data to determine the statistical properties of medium and large horizontal scale (>100 km) gravity waves present in the PMC data. Over 60,000 wave events with horizontal scale-sizes ranging up to >2000 km have been identified and measured, revealing a wealth of wave events particularly in the ~300-800 km range where our analysis sensitivity is largest. These data are ideal for investigating the intra-seasonal, inter-annual and hemispheric variability of these waves as observed over the whole summer polar cap regions. Throughout this 6 year study, the wave activity in the southern hemisphere was found to be consistently 10-15% higher than in the northern hemisphere and both the northern and southern hemisphere wave activity was determined to decrease systematically (by ~15%) during the course of each summer season. This decrease agrees well with previous seasonal stratospheric studies of variations in the wave energy, suggesting a direct influence of the lower atmospheric sources on polar mesospheric dynamics. Very similar and consistent results were also found from season to season in both hemispheres providing new information for gravity wave modeling and dynamical studies of the high-latitude summer-time mesosphere.

  1. Are BVOC exchanges in agricultural ecosystems overestimated? Insights from fluxes measured in a maize field over a whole growing season

    NASA Astrophysics Data System (ADS)

    Bachy, Aurélie; Aubinet, Marc; Schoon, Niels; Amelynck, Crist; Bodson, Bernard; Moureaux, Christine; Heinesch, Bernard

    2016-04-01

    Maize is the most important C4 crop worldwide. It is also the second most important crop worldwide (C3 and C4 mixed), and is a dominant crop in some world regions. Therefore, it can potentially influence local climate and air quality through its exchanges of gases with the atmosphere. Among others, biogenic volatile organic compounds (BVOC) are known to influence the atmospheric composition and thereby modify greenhouse gases lifetime and pollutant formation in the atmosphere. However, so far, only two studies have dealt with BVOC exchanges from maize. Moreover, these studies were conducted on a limited range of meteorological and phenological conditions, so that the knowledge of BVOC exchanges by this crop remains poor. Here, we present the first BVOC measurement campaign performed at ecosystem-scale on a maize field during a whole growing season. It was carried out in the Lonzée Terrestrial Observatory (LTO), an ICOS site. BVOC fluxes were measured by the disjunct by mass-scanning eddy covariance technique with a proton transfer reaction mass spectrometer for BVOC mixing ratios measurements. Outstanding results are (i) BVOC exchanges from soil were as important as BVOC exchanges from maize itself; (ii) BVOC exchanges observed on our site were much lower than exchanges observed by other maize studies, even under normalized temperature and light conditions, (iii) they were also lower than those observed on other crops grown in Europe. Lastly (iv), BVOC exchanges observed on our site under standard environmental conditions, i.e., standard emission factors SEF, were much lower than those currently considered by BVOC exchange up-scaling models. From those observations, we deduced that (i) soil BVOC exchanges should be better understood and should be incorporated in terrestrial BVOC exchanges models, and that (ii) SEF for the C4 crop plant functional type cannot be evaluated at global scale but should be determined for each important agronomic and pedo-climatic region

  2. Leaf Tissue C:N and Soil N are Modified by Growing Season and Goose Grazing Phenology in a Sub-Arctic Coastal Wetland of Western Alaska

    NASA Astrophysics Data System (ADS)

    Choi, R. T.; Beard, K. H.; Leffler, A. J.; Schmutz, J. A.; Welker, J. M.

    2014-12-01

    Climate change in Arctic wetlands is resulting in a widening phenological mismatch between the onset of the growing season and the arrival and hatch date of migratory geese, the primary consumers in the system. During the past three decades, the growing season has advanced but geese have not advanced arrival or hatch date at the same rate. Geese now arrive into a system that has been growing longer than in the past with potential changes in forage quality because sedges have their highest nutrient density shortly following emergence. One potential concomitant result of this phenological gap is altered carbon to nitrogen ratio (C:N) of leaf tissue being returned to the ecosystem as feces that is more N-poor. Altering the C:N of these inputs can further influence C and N cycling in the system. We examine the influence of advanced growing season and different arrival times by black brant on leaf and soil C:N ratio and soil N-form. Our experiment consists of six blocks with nine study plots each. Half the plots are warmed to advance the growing season. Two plots each receive early, typical, late, and no grazing; one plot is a control that is not warmed and grazing is natural. Leaf tissue was collected to determine C and N concentration using an elemental analyzer. Anion and cation exchange membranes were used to monitor inorganic N forms in soil; samples were analyzed via fluorescence following extraction. Soil water collected from lysimeters was analyzed for organic N. Warming advanced plant growth between one and two weeks and resulted in higher C:N of leaf tissue Geese maintained 'grazing lawns', areas of exceptionally short vegetation, where plants had high N compared to non-grazed areas. Grazing early in the season promoted higher N content of leaves and soil while grazing late had little influence on N. The timing of the growing season and grazing both have important implications for C and N in this system.

  3. Forest Gaps Inhibit Foliar Litter Pb and Cd Release in Winter and Inhibit Pb and Cd Accumulation in Growing Season in an Alpine Forest

    PubMed Central

    He, Jie; Yang, Wanqin; Li, Han; Xu, Liya; Ni, Xiangyin; Tan, Bo; Zhao, Yeyi; Wu, Fuzhong

    2015-01-01

    Aims The release of heavy metals (such as Pb and Cd) from foliar litter play an important role in element cycling in alpine forest ecosystems. Although natural forest gaps could play important roles in the release of heavy metals from foliar litter by affecting the snow cover during the winter and solar irradiation during the growing season, few studies have examined these potential roles. The objectives of this study were to document changes in Pb and Cd dynamics during litter decomposition in the center of gaps and under closed canopies and to investigate the factors that controlled these changes during the winter and growing seasons. Methods Senesced foliar litter from six dominant species, including Kangding willow (Salix paraplesia), Masters larch (Larix mastersiana), Mingjiang fir (Abies faxoniana), Alpine azalea (Rhododendron lapponicum), Red birch (Betula albosinensis) and Mourning cypress (Sabina saltuaria), was placed in litterbags and incubated between the gap center and closed canopy conditions in an alpine forest in the eastern region of the Tibetan Plateau. The litterbags were sampled at the snow formation stage, snow coverage stage, snow melt stage and during the growing season. The Pb and Cd concentrations in the sampled foliar litter were determined by acid digestion (HNO3/HClO4). Important findings Over one year of decomposition, Pb accumulation and Cd release from the foliar litter occurred, regardless of the foliar litter species. However, Pb and Cd were both released from the foliar litter during the winter and accumulated during the growing season. Compared with the gap center and the canopy gap edge, the extended gap edge and the closed canopy showed higher Pb and Cd release rates in winter and higher Pb and Cd accumulation rates during the growing season, respectively. Statistical analyses indicate that the dynamics of Pb were significantly influenced by frequent freeze–thaw cycles in winter and appropriate hydrothermal conditions during

  4. Seasonal variations in daily rhythms of activity in athletic horses.

    PubMed

    Bertolucci, C; Giannetto, C; Fazio, F; Piccione, G

    2008-07-01

    Circadian rhythms reflect extensive programming of biological activity that meets and exploits the challenges and opportunities offered by the periodic nature of the environment. In the present investigation, we recorded the total activity of athletic horses kept at four different times of the year (vernal equinox, summer solstice, autumn equinox and winter solstice), to evaluate the presence of seasonal variations of daily activity rhythms. Athletic Thoroughbred horses were kept in individual boxes with paddock. Digitally integrated measure of total activity of each mare was continuously recorded by actigraphy-based data loggers. Horse total activities were not evenly distributed over the day, but they were mainly diurnal during the year. Daily activity rhythms showed clear seasonal variations, with the highest daily amount of activity during the vernal equinox and the lowest during the winter solstice. Interestingly, the amount of activity during either photophase or scotophase changed significantly throughout the year. Circadian analysis of horse activities showed that the acrophase, the estimated time at which the peak of the rhythm occurs, did not change during the year, it always occurred in the middle of the photoperiod. Analysing the time structure of long-term and continuously measured activity and feeding could be a useful method to critically evaluate athletic horse management systems in which spontaneous locomotor activity and feeding are severely limited. Circadian rhythms are present in several elements of sensory motor and psychomotor functions and these would be taken into consideration to plan the training schedules and competitions in athletic horses. PMID:22443706

  5. Investigating Seasonal Gravity Wave Activity in the Summer Polar Mesosphere

    NASA Astrophysics Data System (ADS)

    Zhao, Y.; Taylor, M. J.; Randall, C. E.; Lumpe, J. D., Jr.; Siskind, D. E.; Bailey, S. M.; Russell, J. M., III

    2014-12-01

    The NASA Aeronomy of Ice in the Mesosphere (AIM) satellite is the first satellite mission dedicated to studying polar mesospheric clouds (PMCs). In particular, the Cloud Imaging and Particle Size (CIPS) instrument onboard AIM obtains large-field PMC images enabling a unique investigation of the mesospheric gravity waves, as the satellite traverses over the summer polar regions. The high quality of CIPS data has provided an exceptional capability to investigate the gravity wave signatures in the summer polar mesosphere where previous measurements have been sparse. We have utilized 12 consecutive seasons of AIM/CIPS PMC albedo data to derive the statistical properties of a broad spectrum of gravity waves present in the PMC data. Over 60,000 waves with horizontal scale sizes ranging from ~50 to >2000 km were identified and measured, revealing a well-developed, consistent distribution for their horizontal wavelengths with a peak in occurrence frequency centered around 400 km. The same result was found from season to season and in both hemispheres. Throughout this study, the wave activity in the southern hemisphere was found to be 10-15% higher than in the northern hemisphere and both northern and southern wave activity was found to decrease systematically (average ~15%) during the course of each summer season. We present new results of the intra-seasonal, inter-annual and hemispheric variability of these waves observed over the whole summer polar cap regions. The systematic decrease in wave activity is consistent with background wind filtering in the northern hemisphere but is not apparently associated with the critical level filtering in the southern hemisphere.

  6. Effects of water regime during rice-growing season on annual direct N(2)O emission in a paddy rice-winter wheat rotation system in southeast China.

    PubMed

    Liu, Shuwei; Qin, Yanmei; Zou, Jianwen; Liu, Qiaohui

    2010-01-15

    Annual paddy rice-winter wheat rotation constitutes one of the typical cropping systems in southeast China, in which various water regimes are currently practiced during the rice-growing season, including continuous flooding (F), flooding-midseason drainage-reflooding (F-D-F), and flooding-midseason drainage-reflooding and moisture but without waterlogging (F-D-F-M). We conducted a field experiment in a rice-winter wheat rotation system to gain an insight into the water regime-specific emission factors and background emissions of nitrous oxide (N(2)O) over the whole annual cycle. While flooding led to an unpronounced N(2)O emission during the rice-growing season, it incurred substantial N(2)O emission during the following non-rice season. During the non-rice season, N(2)O fluxes were, on average, 2.61 and 2.48 mg N(2)O-Nm(-)(2) day(-1) for the 250 kg N ha(-1) applied plots preceded by the F and F-D-F water regimes, which are 56% and 49% higher than those by the F-D-F-M water regime, respectively. For the annual rotation system experienced by continuous flooding during the rice-growing season, the relationship between N(2)O emission and nitrogen input predicted the emission factor and background emission of N(2)O to be 0.87% and 1.77 kg N(2)O-Nha(-1), respectively. For the plots experienced by the water regimes of F-D-F and F-D-F-M, the emission factors of N(2)O averaged 0.97% and 0.85%, with background N(2)O emissions of 2.00 kg N(2)O-Nha(-1) and 1.61 kg N(2)O-Nha(-1) for the annual rotation system, respectively. Annual direct N(2)O-N emission was estimated to be 98.1 Gg yr(-1) in Chinese rice-based cropping systems in the 1990s, consisting of 32.3 Gg during the rice-growing season and 65.8 Gg during the non-rice season, which accounts for 25-35% of the annual total emission from croplands in China.

  7. Active toddlers are less likely to grow obese.

    PubMed

    2016-09-12

    Keep toddlers toddling, and you will reduce the chance of them becoming obese in the future. That is the conclusion of a survey of physical activity among pre-school children that relates exercise to body mass index (BMI) scores. PMID:27615574

  8. Activities to Grow On: Buttons, Beads, and Beans.

    ERIC Educational Resources Information Center

    Gonzolis, Amy; And Others

    1992-01-01

    Presents new ideas for using buttons, beans, and beads as teaching manipulatives for elementary school children. The ideas include a button scavenger hunt, a button count, a cup puppet bean game, a numbers guessing game with beans in jars, and a bead stringing activity. (SM)

  9. Ten Years of Growing Season Water, Energy and Carbon Exchange From an Oil sands Reclamation Site, Fort McMurray, Alberta

    NASA Astrophysics Data System (ADS)

    Carey, S. K.; Drewitt, G. B.

    2013-12-01

    The oil sands mining industry in Canada has made a commitment to restore disturbed areas to an equivalent capability to that which existed prior to mining. Certification requires successful reclamation, which can in part be evaluated through long-term ecosystem studies. A reclamation site, informally named South Bison Hill (SBH) has had growing season water, energy and carbon fluxes measured via the eddy covariance method for 10 years since establishment. SBH was capped with a 0.2 m peat-glacial till mixture overlying 0.8 m of reworked glacial till soil. The site was seeded to barley cultivar (Hordeum spp.) in the summer of 2002 and later planted to white spruce (Picea glauca) and aspen (Populus spp.) in the summer/fall of 2004. Since 2007, the major species atop SBH has been aspen, and by 2012 was on average ~ 4 m in height. Climatically, mean growing temperature did not vary greatly, yet there was considerable difference in rainfall among years, with 2012 having the greatest rainfall at 321 mm, whereas 2011 and 2007 were notably dry at 180 and 178 mm, respectively. The partitioning of energy varied among years, but the fraction of latent heat as a portion of net radiation increased with the establishment of aspen, along with concomitant increases in LAI and growing season net ecosystem exchange (NEE). Peat growing season ET was smallest in 2004 at 2.3 mm/d and greatest in 2010 at ~3.9 mm/d. ET rates showed a marked increase in 2008 corresponding with the increase in LAI attributed to the aspen cover. Since the establishment of a surface cover and vegetation in 2003, SBH has been a growing season sink for carbon dioxide. Values of NEE follow similar patterns to those of ET, with values gradually becoming more negative (greater carbon uptake) as the aspen forest established. Comparison with other disturbed and undisturbed boreal aspen stands show that SBH exhibits similar water, energy and carbon flux patterns during the growing season.

  10. The variation of the water deficit during the winter wheat growing season and its impact on crop yield in the North China Plain.

    PubMed

    Wu, Jianjun; Liu, Ming; Lü, Aifeng; He, Bin

    2014-11-01

    The North China Plain (NCP) is one of the main agricultural areas in China. However, it is also widely known for its water shortages, especially during the winter wheat growing season. Recently, climate change has significantly affected the water environment for crop growth. Analyzing the changes in the water deficit, which is only affected by climate factor, will help to improve water management in the NCP. In this study, the Decision Support System for Agrotechnology Transfer (DSSAT) was used to investigate the variations in the water deficit during the winter wheat growing season from 1961 to 2010 in 12 selected stations in the NCP. To represent the changes in the water deficit without any artificial affection, the rainfed simulation was used. Over the past 50 years, the average temperature during the winter wheat growing season increased approximately 1.42 °C. The anthesis date moved forward approximately 7-10 days and to late April, which increased the water demand in April. Precipitation in March and May showed a positive trend, but there was a negative trend in April. The water deficit in late April and early May became more serious than before, with an increasing trend of more than 0.1 mm/year. In addition, because the heading stage, which is very important to crop yield of winter wheat, moved forward, the impact of water deficit in late April was more serious to crop yield. PMID:24531705

  11. Spatiotemporal variations in growing season exchanges of CO2, H2O,and sensible heat in agricultural fields of the Southern GreatPlains

    SciTech Connect

    Fischer, Marc L.; Billesbach, David P.; Berry, Joseph A.; Riley,William J.; Torn, Margaret S.

    2007-06-13

    Climate, vegetation cover, and management create fine-scaleheterogeneity in unirrigated agricultural regions, with important but notwell-quantified consequences for spatial and temporal variations insurface CO2, water, and heat fluxes. We measured eddy covariance fluxesin seven agricultural fields--comprising winter wheat, pasture, andsorghum--in the U.S. Southern Great Plains (SGP) during the 2001-2003growing seasons. Land-cover was the dominant source of variation insurface fluxes, with 50-100 percent differences between fields planted inwinter-spring versus fields planted in summer. Interannual variation wasdriven mainly by precipitation, which varied more than two-fold betweenyears. Peak aboveground biomass and growing-season net ecosystem exchange(NEE) of CO2 increased in rough proportion to precipitation. Based on apartitioning of gross fluxes with a regression model, ecosystemrespiration increased linearly with gross primary production, but with anoffset that increased near the time of seed production. Because theregression model was designed for well-watered periods, it successfullyretrieved NEE and ecosystem parameters during the peak growing season,and identified periods of moisture limitation during the summer. Insummary, the effects of crop type, land management, and water limitationon carbon, water, and energy fluxes were large. Capturing the controllingfactors in landscape scale models will be necessary to estimate theecological feedbacks to climate and other environmental impactsassociated with changing human needs for agricultural production of food,fiber, and energy.

  12. The variation of the water deficit during the winter wheat growing season and its impact on crop yield in the North China Plain

    NASA Astrophysics Data System (ADS)

    Wu, Jianjun; Liu, Ming; Lü, Aifeng; He, Bin

    2014-02-01

    The North China Plain (NCP) is one of the main agricultural areas in China. However, it is also widely known for its water shortages, especially during the winter wheat growing season. Recently, climate change has significantly affected the water environment for crop growth. Analyzing the changes in the water deficit, which is only affected by climate factor, will help to improve water management in the NCP. In this study, the Decision Support System for Agrotechnology Transfer (DSSAT) was used to investigate the variations in the water deficit during the winter wheat growing season from 1961 to 2010 in 12 selected stations in the NCP. To represent the changes in the water deficit without any artificial affection, the rainfed simulation was used. Over the past 50 years, the average temperature during the winter wheat growing season increased approximately 1.42 °C. The anthesis date moved forward approximately 7-10 days and to late April, which increased the water demand in April. Precipitation in March and May showed a positive trend, but there was a negative trend in April. The water deficit in late April and early May became more serious than before, with an increasing trend of more than 0.1 mm/year. In addition, because the heading stage, which is very important to crop yield of winter wheat, moved forward, the impact of water deficit in late April was more serious to crop yield.

  13. The variation of the water deficit during the winter wheat growing season and its impact on crop yield in the North China Plain.

    PubMed

    Wu, Jianjun; Liu, Ming; Lü, Aifeng; He, Bin

    2014-11-01

    The North China Plain (NCP) is one of the main agricultural areas in China. However, it is also widely known for its water shortages, especially during the winter wheat growing season. Recently, climate change has significantly affected the water environment for crop growth. Analyzing the changes in the water deficit, which is only affected by climate factor, will help to improve water management in the NCP. In this study, the Decision Support System for Agrotechnology Transfer (DSSAT) was used to investigate the variations in the water deficit during the winter wheat growing season from 1961 to 2010 in 12 selected stations in the NCP. To represent the changes in the water deficit without any artificial affection, the rainfed simulation was used. Over the past 50 years, the average temperature during the winter wheat growing season increased approximately 1.42 °C. The anthesis date moved forward approximately 7-10 days and to late April, which increased the water demand in April. Precipitation in March and May showed a positive trend, but there was a negative trend in April. The water deficit in late April and early May became more serious than before, with an increasing trend of more than 0.1 mm/year. In addition, because the heading stage, which is very important to crop yield of winter wheat, moved forward, the impact of water deficit in late April was more serious to crop yield.

  14. Bayesian analysis of the species-specific lengthening of the growing season in two European countries and the influence of an insect pest.

    PubMed

    Menzel, Annette; Estrella, Nicole; Heitland, Werner; Susnik, Andreja; Schleip, Christoph; Dose, Volker

    2008-01-01

    A recent lengthening of the growing season in mid and higher latitudes of the northern hemisphere is reported as a clear indicator for climate change impacts. Using data from Germany (1951-2003) and Slovenia (1961-2004), we study whether changes in the start, end, and length of the growing season differ among four deciduous broad-leaved tree species and countries, how the changes are related to temperature changes, and what might be the confounding effects of an insect attack. The functional behaviour of the phenological and climatological time series and their trends are not analysed by linear regression, but by a new Bayesian approach taking into account different models for the functional description (one change-point, linear, constant models). We find advanced leaf unfolding in both countries with the same species order (oak > horse chestnut, beech, and birch). However, this advance is non linear over time and more apparent in Germany with clear change-points in the late 1970s, followed by marked advances (on average 3.67 days decade(-1) in the 2000s). In Slovenia, we find a more gradual advance of onset dates (on average 0.8 days decade(-1) in the 2000s). Leaf colouring of birch, beech, and oak has been slightly delayed in the last 3 decades, especially in Germany, however with no clear functional behaviour. Abrupt changes in leaf colouring dates of horse chestnut with recent advancing onset dates can be linked across countries to damage by a newly emerging pest, the horse chestnut leaf-miner (Cameraria ohridella). The lengthening of the growing season, more distinct in Germany than in Slovenia (on average 4.2 and 1.0 days decade(-1) in the 2000s, respectively), exhibits the same species order in both countries (oak > birch > beech). Damage by horse chestnut leaf-miner leads to reduced lengthening (Germany) and drastic shortening (Slovenia) of the horse chestnut growing season (-12 days decade(-1) in the 2000s). Advanced spring leaf unfolding and lengthening

  15. Seasonal activity and morphological changes in martian gullies

    USGS Publications Warehouse

    Dundas, Colin M.; Diniega, Serina; Hansen, Candice J.; Byrne, Shane; McEwen, Alfred S.

    2012-01-01

    Recent studies of martian dune and non-dune gullies have suggested a seasonal control on present-day gully activity. The timing of current gully activity, especially activity involving the formation or modification of channels (which commonly have been taken as evidence of fluvial processes), has important implications regarding likely gully formation processes and necessary environmental conditions. In this study, we describe the results of frequent meter-scale monitoring of several active gully sites by the High Resolution Imaging Science Experiment (HiRISE) on the Mars Reconnaissance Orbiter (MRO). The aim is to better assess the scope and nature of current morphological changes and to provide improved constraints on timing of gully activity on both dune and non-dune slopes. Our observations indicate that (1) gully formation on Mars is ongoing today and (2) the most significant morphological changes are strongly associated with seasonal frost and defrosting activity. Observed changes include formation of all major components of typical gully landforms, although we have not observed alcove formation in coherent bedrock. These results reduce the need to invoke recent climate change or present-day groundwater seepage to explain the many martian gullies with pristine appearance.

  16. Seasonal variation in nitrogen net uptake and root plasma membrane H+-ATPase activity of Scots pine seedlings as affected by nutrient availability.

    PubMed

    Iivonen, Sari; Vapaavuori, Elina

    2002-01-01

    We examined changes in nitrogen (N) net uptake and activity and amount of plasma membrane H+-ATPase (PM-ATPase) in roots of hydroponically cultured Scots pine (Pinus sylvestris L.) seedlings throughout a simulated second growing season. Seedlings were grown with low (0.25 mM N) or high (2.5 mM N) nutrient availability to determine whether root PM-ATPase is dependent on an external nutrient supply. Climatic conditions in the growth chamber simulated the mean growing season from May to mid-October in southern Finland. Root PM-ATPase activity varied considerably during the growing season and was higher in current-year roots than in previous-year roots. Total PM-ATPase activity of current-year roots was highest at the end of the growing season, whereas PM-ATPase activity per unit fresh mass of current-year roots and specific absorption rate of N were highest in mid-July and decreased at the end of the growing season. This indicates that the decrease in PM-ATPase activity per unit fresh mass of the roots at the end of the growing season was compensated by the increased size of the root system. Seasonal variation in PM-ATPase activity had no clear dependence on root zone temperature. The response of PM-ATPase to root zone temperature was dependent on the developmental stage of the seedling. High nutrient availability resulted in increased root PM-ATPase activity and an extended period of root growth in autumn. PMID:11772550

  17. Sensory and chemical flavor analyses of tomato genotypes grown in Florida during three different growing seasons in multiple years

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Thirty-eight tomato genotypes were analyzed for sensory attributes “sweet”, “sour” and “overall flavor” over seven years, one to three seasons per year (March, June and December) as well as for physical and chemical flavor-related attributes including color, sugars, acids and aroma volatiles (6-7 ye...

  18. Ideal free distribution of metabolic activity: Implications of seasonal metabolic-activity patterns on competitive coexistence.

    PubMed

    Szabó, Péter

    2016-10-01

    The seasonal distribution of metabolic activity determines how much individuals experience different aspects of a periodically changing environment. Seasonal metabolic-activity patterns of coexisting species may differ significantly despite their shared environmental conditions, suggesting that interspecific diversification of this trait has a major role in the coexistence of competing species. In the present study the effect of the seasonal distribution of metabolic activity on intra- and interspecific competition is investigated in a consumer-resource model. It is shown that, in a periodically changing environment, for each environmental preference pattern there is an ideal seasonal distribution of metabolic activity, which results in maximum resource utilisation efficiency and competitive superiority. Contrary to the common interpretation of temporal niche segregation, opposing species-specific seasonal preferences are not a sufficient condition for the coexistence of two species on a population dynamical time scale. A necessary and sufficient condition for coexistence is the temporal segregation of the species via different seasonal activity distributions. However, coexistence is evolutionarily stable only if seasonal metabolic activities and preferences are positively correlated. PMID:27189108

  19. Seasonal Pacing - Match Importance Affects Activity in Professional Soccer

    PubMed Central

    Link, Daniel; de Lorenzo, Michael F.

    2016-01-01

    This research explores the influence of match importance on player activity in professional soccer. Therefore, we used an observational approach and analyzed 1,211 matches of German Bundesliga and 2nd Bundesliga. The importance measurement employed is based on post season consequences of teams involved in a match. This means, if a match result could potentially influence the final rank, and this rank would lead to different consequences for a team, such as qualification for Champions League opposed to qualification for Europe League, then this match is classified as important; otherwise not. Activity was quantified by TOTAL DISTANCE COVERED, SPRINTS, FAST RUNS, DUELS, FOULS and ATTEMPTS. Running parameters were recorded using a semi-automatic optical tracking system, while technical variables were collected by professional data loggers. Based on our importance classification, low important matches occurred at the beginning of round 29. A two-way ANOVA indicates significantly increased FAST RUNS (+4%, d = 0.3), DUELS (+16%, d = 1.0) and FOULS (+36%, d = 1.2) in important matches compared to low important ones. For FAST RUNS and FOULS, this effect only exists in Bundesliga. A comparison of the two leagues show that TOTAL DISTANCE COVERED (+3%, d = 0.9), SPRINTS (+25%, d = 1.4) and FAST RUNS (+15%, d = 1.4) are higher compared to 2nd Bundesliga, whilst FOULS is less in Bundesliga (-7%, d = 0.3). No difference in player activity was found between matches at the beginning of a season (round 1–6) and at the end of a season (round 29–34). We conclude that match importance influences player activity in German professional soccer. The most reasonable explanation is a conscious or unconscious pacing strategy, motivated by preserving abilities or preventing injury. Since this tendency mainly exists in Bundesliga, this may suggest that more skilled players show a higher awareness for the need of pacing. PMID:27281051

  20. Seasonal Pacing - Match Importance Affects Activity in Professional Soccer.

    PubMed

    Link, Daniel; de Lorenzo, Michael F

    2016-01-01

    This research explores the influence of match importance on player activity in professional soccer. Therefore, we used an observational approach and analyzed 1,211 matches of German Bundesliga and 2nd Bundesliga. The importance measurement employed is based on post season consequences of teams involved in a match. This means, if a match result could potentially influence the final rank, and this rank would lead to different consequences for a team, such as qualification for Champions League opposed to qualification for Europe League, then this match is classified as important; otherwise not. Activity was quantified by TOTAL DISTANCE COVERED, SPRINTS, FAST RUNS, DUELS, FOULS and ATTEMPTS. Running parameters were recorded using a semi-automatic optical tracking system, while technical variables were collected by professional data loggers. Based on our importance classification, low important matches occurred at the beginning of round 29. A two-way ANOVA indicates significantly increased FAST RUNS (+4%, d = 0.3), DUELS (+16%, d = 1.0) and FOULS (+36%, d = 1.2) in important matches compared to low important ones. For FAST RUNS and FOULS, this effect only exists in Bundesliga. A comparison of the two leagues show that TOTAL DISTANCE COVERED (+3%, d = 0.9), SPRINTS (+25%, d = 1.4) and FAST RUNS (+15%, d = 1.4) are higher compared to 2nd Bundesliga, whilst FOULS is less in Bundesliga (-7%, d = 0.3). No difference in player activity was found between matches at the beginning of a season (round 1-6) and at the end of a season (round 29-34). We conclude that match importance influences player activity in German professional soccer. The most reasonable explanation is a conscious or unconscious pacing strategy, motivated by preserving abilities or preventing injury. Since this tendency mainly exists in Bundesliga, this may suggest that more skilled players show a higher awareness for the need of pacing.

  1. Seasonal Pacing - Match Importance Affects Activity in Professional Soccer.

    PubMed

    Link, Daniel; de Lorenzo, Michael F

    2016-01-01

    This research explores the influence of match importance on player activity in professional soccer. Therefore, we used an observational approach and analyzed 1,211 matches of German Bundesliga and 2nd Bundesliga. The importance measurement employed is based on post season consequences of teams involved in a match. This means, if a match result could potentially influence the final rank, and this rank would lead to different consequences for a team, such as qualification for Champions League opposed to qualification for Europe League, then this match is classified as important; otherwise not. Activity was quantified by TOTAL DISTANCE COVERED, SPRINTS, FAST RUNS, DUELS, FOULS and ATTEMPTS. Running parameters were recorded using a semi-automatic optical tracking system, while technical variables were collected by professional data loggers. Based on our importance classification, low important matches occurred at the beginning of round 29. A two-way ANOVA indicates significantly increased FAST RUNS (+4%, d = 0.3), DUELS (+16%, d = 1.0) and FOULS (+36%, d = 1.2) in important matches compared to low important ones. For FAST RUNS and FOULS, this effect only exists in Bundesliga. A comparison of the two leagues show that TOTAL DISTANCE COVERED (+3%, d = 0.9), SPRINTS (+25%, d = 1.4) and FAST RUNS (+15%, d = 1.4) are higher compared to 2nd Bundesliga, whilst FOULS is less in Bundesliga (-7%, d = 0.3). No difference in player activity was found between matches at the beginning of a season (round 1-6) and at the end of a season (round 29-34). We conclude that match importance influences player activity in German professional soccer. The most reasonable explanation is a conscious or unconscious pacing strategy, motivated by preserving abilities or preventing injury. Since this tendency mainly exists in Bundesliga, this may suggest that more skilled players show a higher awareness for the need of pacing. PMID:27281051

  2. Cherry tomatoes metabolic profile determined by ¹H-High Resolution-NMR spectroscopy as influenced by growing season.

    PubMed

    Masetti, Olimpia; Ciampa, Alessandra; Nisini, Luigi; Valentini, Massimiliano; Sequi, Paolo; Dell'Abate, Maria Teresa

    2014-11-01

    The content of the most valuable metabolites present in the lipophilic fraction of Protected Geographical Indication cherry tomatoes produced in Pachino (Italy) was observed for 2 cultivated varieties, i.e. cv. Naomi and cv. Shiren, over a period of 3 years in order to observe variations due to relevant climatic parameters, e.g. solar radiation and average temperature, characterising different seasons. (1)H-NMR spectroscopy was applied and spectral data were processed by means of Principal Component Analysis (PCA). We found that the metabolic profile was different for the two considered cultivated varieties and they were differently affected by climatic conditions. Major metabolites influenced by cropping period were α-tocopherol and the unsaturated lipid fraction in Naomi cherry tomatoes, and chlorophylls and phospholipids in Shiren variety, respectively. These results furnished useful information on seasonal dynamics of such important nutritional metabolites contained in tomatoes, confirming also NMR spectroscopy as powerful tool to define a complete metabolic profiling. PMID:24874378

  3. Nocturnal and seasonal activities of the pallid bat, Antrozous pallidus

    USGS Publications Warehouse

    O'Shea, Thomas J.; Vaughan, Terry A.

    1977-01-01

    Nocturnal and seasonal activities of pallid bats (Antrozous pallidus) were observed in central Arizona. The pallid bat night is characterized by two roaming periods with an intervening period of night roosting. Foraging pallid bats have a characteristic style of flight well suited to the taking of relatively large, substrate-roving or slow flying prey. After the initial foraging period pallid bats locate one another through vocal communication and gather in night roosting clusters where they enter torpor. Durations and scheduling of nocturnal activities vary seasonally. Cool months are characterized by smaller colonies of bats, greater fidelity to certain colony sites, slower and later emergence, briefer foraging periods and longer periods of night roosting. Up to 75 percent of the time spent away from diurnal retreats is devoted to night roosting in the autumn. Young are born in June, and during most of the summer adult males do not seem to occur sympatrically with females and young. Females and young appear to forage together in July and August, when little fidelity is shown to roosting sites, large colonies exist, emergence is faster and earlier, and more time is spent in foraging than in cooler months. In mid-August a postbreeding dispersal occurs. These activities and behaviors are discussed in terms of the energetic demands on the bats and the socialization of young.

  4. The growing season, but not the farming system, is a food safety risk determinant for leafy greens in the mid-Atlantic region of the United States.

    PubMed

    Marine, Sasha C; Pagadala, Sivaranjani; Wang, Fei; Pahl, Donna M; Melendez, Meredith V; Kline, Wesley L; Oni, Ruth A; Walsh, Christopher S; Everts, Kathryne L; Buchanan, Robert L; Micallef, Shirley A

    2015-04-01

    Small- and medium-size farms in the mid-Atlantic region of the United States use varied agricultural practices to produce leafy greens during spring and fall, but the impact of preharvest practices on food safety risk remains unclear. To assess farm-level risk factors, bacterial indicators, Salmonella enterica, and Shiga toxin-producing Escherichia coli (STEC) from 32 organic and conventional farms were analyzed. A total of 577 leafy greens, irrigation water, compost, field soil, and pond sediment samples were collected. Salmonella was recovered from 2.2% of leafy greens (n = 369) and 7.7% of sediment (n = 13) samples. There was an association between Salmonella recovery and growing season (fall versus spring) (P = 0.006) but not farming system (organic or conventional) (P = 0.920) or region (P = 0.991). No STEC was isolated. In all, 10% of samples were positive for E. coli: 6% of leafy greens, 18% of irrigation water, 10% of soil, 38% of sediment, and 27% of compost samples. Farming system was not a significant factor for levels of E. coli or aerobic mesophiles on leafy greens but was a significant factor for total coliforms (TC) (P < 0.001), with higher counts from organic farm samples. Growing season was a factor for aerobic mesophiles on leafy greens (P = 0.004), with higher levels in fall than in spring. Water source was a factor for all indicator bacteria (P < 0.001), and end-of-line groundwater had marginally higher TC counts than source samples (P = 0.059). Overall, the data suggest that seasonal events, weather conditions, and proximity of compost piles might be important factors contributing to microbial contamination on farms growing leafy greens.

  5. The Growing Season, but Not the Farming System, Is a Food Safety Risk Determinant for Leafy Greens in the Mid-Atlantic Region of the United States

    PubMed Central

    Marine, Sasha C.; Pagadala, Sivaranjani; Wang, Fei; Pahl, Donna M.; Melendez, Meredith V.; Kline, Wesley L.; Oni, Ruth A.; Walsh, Christopher S.; Everts, Kathryne L.; Buchanan, Robert L.

    2015-01-01

    Small- and medium-size farms in the mid-Atlantic region of the United States use varied agricultural practices to produce leafy greens during spring and fall, but the impact of preharvest practices on food safety risk remains unclear. To assess farm-level risk factors, bacterial indicators, Salmonella enterica, and Shiga toxin-producing Escherichia coli (STEC) from 32 organic and conventional farms were analyzed. A total of 577 leafy greens, irrigation water, compost, field soil, and pond sediment samples were collected. Salmonella was recovered from 2.2% of leafy greens (n = 369) and 7.7% of sediment (n = 13) samples. There was an association between Salmonella recovery and growing season (fall versus spring) (P = 0.006) but not farming system (organic or conventional) (P = 0.920) or region (P = 0.991). No STEC was isolated. In all, 10% of samples were positive for E. coli: 6% of leafy greens, 18% of irrigation water, 10% of soil, 38% of sediment, and 27% of compost samples. Farming system was not a significant factor for levels of E. coli or aerobic mesophiles on leafy greens but was a significant factor for total coliforms (TC) (P < 0.001), with higher counts from organic farm samples. Growing season was a factor for aerobic mesophiles on leafy greens (P = 0.004), with higher levels in fall than in spring. Water source was a factor for all indicator bacteria (P < 0.001), and end-of-line groundwater had marginally higher TC counts than source samples (P = 0.059). Overall, the data suggest that seasonal events, weather conditions, and proximity of compost piles might be important factors contributing to microbial contamination on farms growing leafy greens. PMID:25616798

  6. The Characterization of Extreme Episodes of Wet and Dry Deposition of Pollutants on an Above Cloud-Base Forest during its Growing Season.

    NASA Astrophysics Data System (ADS)

    Defelice, T. P.; Saxena, V. K.

    1991-11-01

    An analysis of a 3-yr database (1986-88) acquired new Mount Mitchell (35°4405N, 82°1715W, 2038 m MSL) where the forest consists primarily of Fraser fir and some red spruce stands is presented. The site was immersed in clouds for 28%-41% of the time during each of the three growing seasons (15 May-15 September). This study only investigated extreme episodes of wet (cloud-water pH% .3:1)and dry (eg., an ozone concentration 70 ppb) acidic deposition. Extreme wet events occasionally relieved periods of high ozone ( 70 ppb) exposures during the final field intensive. Extreme wet and dry events could activate the decline mechanism in any above cloud-base forest, especially if the trees are exposed to such events during very early or very late stages of their Lives. The exposure of the forest to natural climatic stress, such as drought condition wintertime temperatures during the growing season, snow storm during early spring, etc., would also subject the forest to a stressful period during which the exposure to the aforementioned episodes of pollutant deposition might trigger a decline.On the average, one of three cloud events that traverse this site is extreme. These extreme events usually last about 4 h. form during periods of high atmospheric pressure, have a liquid water content of 0.10 g m3, and contain cloud droplets of mean diameter around 8.0 m. During the dissipating stages, such cloud events result in maximum acidic deposition. When such events are preceded by very high ozone ( 100 ppb), they may prove oven more detrimental to forest health. A precipitating cloud event (pH = 4.4 on the average) preceded by periods of very high ozone concentrations will become an extreme episode. Extreme acidic events can occur in association with 1) an 850-mb closed low, situated just north of Montreal, Canada, that advances southward into New York State, and 2) an 850-mb high extending over the Gulf of Mexico (between Florida and Louisiana) to over eastern Kansas. In

  7. Environmental factors controlling forest evapotranspiration and surface conductance on a multi-temporal scale in growing seasons of a Siberian larch forest

    NASA Astrophysics Data System (ADS)

    Yoshida, Megumi; Ohta, Takeshi; Kotani, Ayumi; Maximov, Trofim

    2010-12-01

    SummaryThe water and energy fluxes in forests fluctuate on different temporal scales, reflecting the impact of environmental factors. We examined the temporal fluctuation of the turbulent fluxes, surface conductance ( Gs), and four environmental factors (photosynthetic photon flux density [ Q], vapour pressure deficit [ D], air temperature [ T], and volumetric soil water content [ θ]) in a Siberian larch forest, using wavelet power spectra. The responses of the latent heat flux ( λE) and Gs to the environmental factors were analysed using the wavelet scale-wise correlation coefficient (SWCC) on multiple temporal scales. The observation site is characterised by underlying permafrost and a relatively short growing season. Analysis was conducted from May to September in each of 8 years during 1998-2007. The relationships between Gs and the environmental factors were evaluated with restrictive functions of a Jarvis-type surface conductance model because Gs usually has non-linear relationships to ambient factors. According to the power spectra of each factor, the largest variation was seen on a diurnal timescale for λE, the sensible heat flux ( H), Gs, and Q, whereas D and T fluctuated from diurnal to inter-seasonal timescales, and θ varied significantly over periods longer than the inter-seasonal timescales. The SWCC indicated that λE and Gs respond differently to the same ambient factors due to their respective processes; namely, λE is affected by both atmospheric demand and land surface regulation, whereas Gs is affected only by the latter. λE correlated well with Q at all timescales, as well as with D and T on intra-seasonal to interannual scales and with θ on inter-seasonal to interannual timescales. The SWCC of Gs and Q showed two peaks, on diurnal and inter-seasonal to interannual timescales, reflecting the physiological processes of plants, and D affected Gs only on an intra-seasonal timescale, which is related to meteorological changes. T and

  8. Restoring fire as an ecological process in shortgrass prairie ecosystems: initial effects of prescribed burning during the dormant and growing seasons.

    PubMed

    Brockway, Dale G; Gatewood, Richard G; Paris, Randi B

    2002-06-01

    Prior to Anglo-European settlement, fire was a major ecological process influencing the structure, composition and productivity of shortgrass prairie ecosystems on the Great Plains. However during the past 125 years, the frequency and extent of grassland fire has dramatically declined as a result of the systematic heavy grazing by large herds of domestic cattle and sheep which reduced the available levels of fine fuel and organized fire suppression efforts that succeeded in altering the natural fire regime. The greatly diminished role of recurrent fire in these ecosystems is thought to be responsible for ecologically adverse shifts in the composition, structure and diversity of these grasslands, leading specifically to the rise of ruderal species and invasion by less fire-tolerant species. The purpose of this study was to evaluate the ecological effects of fire season and frequency on the shortgrass prairie and to determine the means by which prescribed fire can best be restored in this ecosystem to provide the greatest benefit for numerous resource values. Plant cover, diversity, biomass and nutrient status, litter cover and soil chemistry were measured prior to and following fire treatments on a buffalograss-blue grama shortgrass prairie in northeastern New Mexico. Dormant-season fire was followed by increases in grass cover, forb cover, species richness and concentrations of foliar P, K, Ca, Mg and Mn. Growing-season fire produced declines in the cover of buffalograss, graminoids and forbs and increases in litter cover and levels of foliar P, K, Ca and Mn. Although no changes in soil chemistry were observed, both fire treatments caused decreases in herbaceous production, with standing biomass resulting from growing-season fire approximately 600 kg/ha and dormant-season fire approximately 1200 kg/ha, compared with controls approximately 1800 kg/ha. The initial findings of this long-term experiment suggest that dormant-season burning may be the preferable method

  9. Restoring fire as an ecological process in shortgrass prairie ecosystems: initial effects of prescribed burning during the dormant and growing seasons.

    PubMed

    Brockway, Dale G; Gatewood, Richard G; Paris, Randi B

    2002-06-01

    Prior to Anglo-European settlement, fire was a major ecological process influencing the structure, composition and productivity of shortgrass prairie ecosystems on the Great Plains. However during the past 125 years, the frequency and extent of grassland fire has dramatically declined as a result of the systematic heavy grazing by large herds of domestic cattle and sheep which reduced the available levels of fine fuel and organized fire suppression efforts that succeeded in altering the natural fire regime. The greatly diminished role of recurrent fire in these ecosystems is thought to be responsible for ecologically adverse shifts in the composition, structure and diversity of these grasslands, leading specifically to the rise of ruderal species and invasion by less fire-tolerant species. The purpose of this study was to evaluate the ecological effects of fire season and frequency on the shortgrass prairie and to determine the means by which prescribed fire can best be restored in this ecosystem to provide the greatest benefit for numerous resource values. Plant cover, diversity, biomass and nutrient status, litter cover and soil chemistry were measured prior to and following fire treatments on a buffalograss-blue grama shortgrass prairie in northeastern New Mexico. Dormant-season fire was followed by increases in grass cover, forb cover, species richness and concentrations of foliar P, K, Ca, Mg and Mn. Growing-season fire produced declines in the cover of buffalograss, graminoids and forbs and increases in litter cover and levels of foliar P, K, Ca and Mn. Although no changes in soil chemistry were observed, both fire treatments caused decreases in herbaceous production, with standing biomass resulting from growing-season fire approximately 600 kg/ha and dormant-season fire approximately 1200 kg/ha, compared with controls approximately 1800 kg/ha. The initial findings of this long-term experiment suggest that dormant-season burning may be the preferable method

  10. Deconvolution of pigment and physiologically related photochemical reflectance index variability at the canopy scale over an entire growing season.

    PubMed

    Hmimina, G; Merlier, E; Dufrêne, E; Soudani, K

    2015-08-01

    The sensitivity of the photochemical reflectance index (PRI) to leaf pigmentation and its impacts on its potential as a proxy for light-use efficiency (LUE) have recently been shown to be problematic at the leaf scale. Most leaf-to-leaf and seasonal variability can be explained by such a confounding effect. This study relies on the analysis of PRI light curves that were generated at the canopy scale under natural conditions to derive a precise deconvolution of pigment-related and physiologically related variability in the PRI. These sources of variability were explained by measured or estimated physiologically relevant variables, such as soil water content, that can be used as indicators of water availability and canopy chlorophyll content. The PRI mainly reflected the variability in the pigment content of the canopy. However, the corrected PRI, which was obtained by subtracting the pigment-related seasonal variability from the PRI measurement, was highly correlated with the upscaled LUE measurements. Moreover, the sensitivity of the PRI to the leaf pigment content may mask the PRI versus LUE relationship or result in an artificial relationship that reflects the relationship of chlorophyll versus LUE, depending on the species phenology.

  11. Determining of the Effect of Lysine:calorie Ratio on Growth Performance and Blood Urea Nitrogen of Growing Barrows and Gilts in Hot Season and Cool Season in a Commercial Environment.

    PubMed

    Zhang, Z F; Kim, I H

    2013-03-01

    Two experiments were conducted to determine an optimum Lys:calorie ratio (g of total dietary Lys/Mcal of DE) for growing barrows and gilts in cool and hot seasons in a commercial environment. In Exp. 1, 96 barrows and 96 gilts were randomly allocated in 1 of 4 dietary treatments (2.7, 3.0, 3.3, 3.6 g of Lys/Mcal of DE). Each treatment had 12 replicate pens with 4 pigs per pen. The experiment lasted for 34 d in the cool season (March 12th to April 15th). Diets were based on corn-wheat-soybean meal. Lys:calorie ratio were attained by adjusting the amount of corn and soybean and supplementation of crystalline Lys. Total Lys intake and available Lys intake were increased (p<.05) as dietary Lys:calorie ratio increased. The BUN concentration on d 34 for barrows, and BUN change for barrows and gilts linearly increased (p<0.05) in response to increasing dietary Lys:calorie ratio. For gilts, back fat was decreased and then increased (Quadratically, p<0.05) as increasing dietary lys:calorie ratio. Exp. 2 had a similar design as Exp. 1 with the exception that Exp. 2 was conducted in hot season (June 30th to September 11th) for 42 d. Diet of Exp. 2 was the same as Exp. 1. Total Lys intake and available Lys intake increased (p<0.05) as dietary Lys:calorie increased. On d 42, the BUN concentration increased (p<0.05) in response to the increasing dietary Lys:calorie ratio. In conclusion, dietary Lys:calorie ratio of 2.7 g of Lys/Mcal of DE could satisfy the requirement of 25 to 50 kg growing pigs. Increasing dietary Lys:calorie ratio could increase BUN concentration in growing pigs.

  12. Interactions between light and growing season temperatures on, growth and development and gas exchange of Semillon (Vitis vinifera L.) vines grown in an irrigated vineyard.

    PubMed

    Greer, Dennis H; Weedon, Mark M

    2012-05-01

    High-light intensities and temperatures of the warm climate regions of Australia and elsewhere have a major effect on the growth and development of grapevines (Vitis vinifera L.). The objective of this research was to assess interactions between the light and seasonal temperatures by shading some vines and comparing these with vines exposed to high-light intensities. Canopy temperatures were monitored using infrared radiometers and budbreak, phenology, growth, yield, berry ripening and gas exchange determined over three growing seasons. Results showed canopies were generally about 4 °C cooler than air and shading extended this cooling. Irradiance, irrespective of seasonal temperatures, had no effect on time of budbreak, shoot phenology, stem growth, yield and bunch fresh weights while bunch and leaf dry weights were reduced in low-light. Bunch ripening was initially delayed by low-light but thereafter the ripening process was highly temperature-dependent. Rates increased linearly with increasing temperature in both low and high-light and were optimal at about 35 °C. Maximum photosynthetic capacity was impaired by low irradiance, in accordance with shade leaf attributes, and attributable to stomatal closure. No effects of the low photosynthetic capacity apparently carried-over to sugar accumulation, consistent with the strong sink capacity of bunches.

  13. Monitoring seasonal progress of rice stubble burning in major rice growing districts of Haryana, India, using multidate AWiFS data

    NASA Astrophysics Data System (ADS)

    Yadav, M.; Prawasi, R.; Jangra, S.; Rana, P.; Kumari, K.; Lal, S.; Jakhar, K.; Sharma, S.; Hooda, R. S.

    2014-11-01

    The present paper describes the methodology and results of assessment of seasonal progress of rice stubble burning for 10 major rice growing districts of Haryana state in India. These 10 districts contribute about 84 per cent of total rice area of the state. As the rice fields are immediately required to be vacated for the sowing of next crop the farmers opt for mechanized harvesting and easy way out of burning the stubbles in the field. Such burning result in release of polluting gases and aerosols. Besides, the heating of the soil kills the useful micro-flora of the soil causing soil degradation. Multi-date AWiFS data from Resourcesat 1 and 2 satellites acquired between October 16, 2013 to November 26, 2013 were used for estimating paddy stubble burning areas at different intervals for the year 2013 crop growing season. In season collected ground truth data using hand held GPS along with field photographs were used to identify paddy stubble burning areas and other land features. Complete enumeration approach and Iterative Self-organizing Data Analysis Technique (ISODATA) unsupervised classifier was used for digital analysis. Normalized Difference Vegetation Index (NDVI) of each date was also used with other spectral bands of temporal images. To improve the classification accuracy the non-agricultural areas were masked out. The area was estimated by computing pixels under the classified image mask. Progress of paddy stubble burning was estimated at different intervals for the year 2013 using available cloud free multi-date IRS-P6 AWiFS data to identify the crucial period when stubbles burning takes place in major area so that preventive measures can be taken to curb the menace.

  14. Determination of insecticidal Cry1Ab protein in soil collected in the final growing seasons of a nine-year field trial of Bt-maize MON810.

    PubMed

    Gruber, Helga; Paul, Vijay; Meyer, Heinrich H D; Müller, Martin

    2012-02-01

    Cultivation of genetically modified maize (Bt-maize; event MON810) producing recombinant δ-endotoxin Cry1Ab, leads to introduction of the insecticidal toxin into soil by way of root exudates and plant residues. This study investigated the fate of Cry1Ab in soil under long-term Bt-maize cultivation in an experimental field trial performed over nine growing seasons on four South German field sites cultivated with MON810 and its near isogenic non Bt-maize variety. Cry1Ab protein was quantified in soil (<2 mm size) using an in-house validated ELISA method. The assay was validated according to the criteria specified in European Commission Decision 2002/657/EC. The assay enabled quantification of Cry1Ab protein at a decision limit (CCα) of 2.0 ng Cry1Ab protein g(-1) soil with analytical recovery in the range 49.1-88.9%, which was strongly correlated with clay content. Cry1Ab protein was only detected on one field site at concentrations higher than the CCα, with 2.91 and 2.57 ng Cry1Ab protein g(-1) soil in top and lower soil samples collected 6 weeks after the eighth growing season. Cry1Ab protein was never detected in soil sampled in the spring before the next farming season at any of the four experimental sites. No experimental evidence for accumulation or persistence of Cry1Ab protein in different soils under long-term Bt-maize cultivation can be drawn from this field study.

  15. Effect of species of cool-season annual grass interseeded into Bermudagrass sod on the performance of growing calves.

    PubMed

    Beck, P A; Stewart, C B; Phillips, J M; Watkins, K B; Gunter, S A

    2007-02-01

    Two experiments were conducted to evaluate the effect of species of cool-season annual grass on the growth of stocker cattle over 3 yr. In Exp. 1, the small grains (SG) oat (O), rye (R), and wheat (W), or combinations of SG and annual ryegrass (RG), were interseeded into Bermudagrass sod in a completely randomized design with a 3 x 2 factorial arrangement of treatments. In Exp. 2, RG was planted alone or with O, R, triticale (T), or W in a completely randomized design. Pastures were planted in late October of each year, and seeding rates were 134.4 and 22.4 kg/ha for SG and RG, respectively. In Exp. 1, grazing was initiated on December 18. In Exp. 2, grazing was initiated on December 23 for SG pastures and January 21 or February 16 for RG pastures in yr 1 and on December 8 for all pastures in yr 2. Grazing was managed using the put-and-take method, in which additional calves were added as needed to maintain equal grazing pressure among pastures. In Exp. 1, no interactions (P > or = 0.28) were detected, so the main effects of SG species and RG addition are discussed. From December 18 to March 12, there were no differences in ADG (P > or = 0.17), whereas during the spring (from March 12 to May 7), addition of RG increased (P = 0.05) ADG. Using RG increased (P < or = 0.01) animal grazing-days/hectare and BW gain/hectare. Wheat tended (P = 0.08) to increase BW gain/hectare compared with the other SG, and O tended (P = 0.09) to produce less BW gain/hectare than the other SG. The treatment x year interaction was significant (P < or = 0.05) in Exp. 2. In yr 1, no differences (P = 0.25) were observed for ADG from December 23 to March 8, but during the spring grazing period (from March 8 to May 5), ADG of calves grazing TRG was less (P < or = 0.04) than that of those grazing RG, RRG, or WRG. The RRG combination produced more (P < or = 0.03) BW gain/hectare than ORG, RG, or TRG and tended (P = 0.06) to produce more BW gain/hectare than WRG. The WRG combination produced more

  16. The contribution of soil biogenic NO emissions from a managed hyper-arid ecosystem to the regional NO2 emissions during growing season

    NASA Astrophysics Data System (ADS)

    Mamtimin, B.; Badawy, M.; Behrendt, T.; Meixner, F. X.; Wagner, T.

    2015-12-01

    A study was carried out to understand the contributions of soil biogenic NO emissions from managed (fertilized and irrigated) hyper-arid ecosystem in NW-China to the regional NO2 emissions during growing season. Soil biogenic NO emissions were quantified by laboratory incubation of corresponding soil samples. We have developed the Geoscience General Tool Package (GGTP) to obtain soil temperature, soil moisture and biogenic soil NO emission at oasis scale. Bottom-up anthropogenic NO2 emissions have been scaled down from annual to monthly values to compare mean monthly soil biogenic NO2 emissions. The top-down emission estimates have been derived from satellite observations compared then with the bottom-up emission estimates (anthropogenic and biogenic). The results show that the soil biogenic emissions of NO2 during the growing period are (at least) equal until twofold of the related anthropogenic sources. We found that the grape soils are the main summertime contributor to the biogenic NO emissions of study area, followed by cotton soils. The top-down and bottom-up emission estimates were shown to be useful methods to estimate the monthly/seasonal cycle of the total regional NO2 emissions. The resulting total NO2 emissions show a strong peak in winter and a secondary peak in summer, providing confidence in the method. These findings provide strong evidence that biogenic emissions from soils of managed drylands (irrigated and fertilized) in the growing period can be much more important contributors to the regional NO2 budget (hence to regional photochemistry) of dryland regions than thought before.

  17. Chemical composition, antioxidant and antimicrobial activities of basil (Ocimum basilicum) essential oils depends on seasonal variations.

    PubMed

    Hussain, Abdullah Ijaz; Anwar, Farooq; Hussain Sherazi, Syed Tufail; Przybylski, Roman

    2008-06-01

    Chemical composition, antioxidant and antimicrobial activities of the essential oils from aerial parts of basil (Ocimum basilicum L.) as affected by four seasonal, namely summer, autumn, winter and spring growing variation were investigated. The hydro-distilled essential oils content ranged from 0.5% to 0.8%, the maximum amounts were observed in winter while minimum in summer. The essential oils consisted of linalool as the most abundant component (56.7-60.6%), followed by epi-α-cadinol (8.6-11.4%), α-bergamotene (7.4-9.2%) and γ-cadinene (3.2-5.4%). Samples collected in winter were found to be richer in oxygenated monoterpenes (68.9%), while those of summer were higher in sesquiterpene hydrocarbons (24.3%). The contents of most of the chemical constituents varied significantly (p<0.05) with different seasons. The essential oils investigated, exhibited good antioxidant activity as measurements by DPPH free radical-scavenging ability, bleaching β-carotene in linoleic acid system and inhibition of linoleic acid oxidation. Evaluation of antimicrobial activity of the essential oils and linalool, the most abundant component, against bacterial strains: Staphylococcus aureus, Escherichia coli, Bacillus subtilis, Pasteurella multocida and pathogenic fungi Aspergillus niger, Mucor mucedo, Fusarium solani, Botryodiplodia theobromae, Rhizopus solani was assessed by disc diffusion method and measurement of determination of minimum inhibitory concentration. The results of antimicrobial assays indicated that all the tested microorganisms were affected. Both the antioxidant and antimicrobial activities of the oils varied significantly (p<0.05), as seasons changed.

  18. Structure of the rare archaeal biosphere and seasonal dynamics of active ecotypes in surface coastal waters

    PubMed Central

    Hugoni, Mylène; Taib, Najwa; Debroas, Didier; Domaizon, Isabelle; Jouan Dufournel, Isabelle; Bronner, Gisèle; Salter, Ian; Agogué, Hélène; Mary, Isabelle; Galand, Pierre E.

    2013-01-01

    Marine Archaea are important players among microbial plankton and significantly contribute to biogeochemical cycles, but details regarding their community structure and long-term seasonal activity and dynamics remain largely unexplored. In this study, we monitored the interannual archaeal community composition of abundant and rare biospheres in northwestern Mediterranean Sea surface waters by pyrosequencing 16S rDNA and rRNA. A detailed analysis of the rare biosphere structure showed that the rare archaeal community was composed of three distinct fractions. One contained the rare Archaea that became abundant at different times within the same ecosystem; these cells were typically not dormant, and we hypothesize that they represent a local seed bank that is specific and essential for ecosystem functioning through cycling seasonal environmental conditions. The second fraction contained cells that were uncommon in public databases and not active, consisting of aliens to the studied ecosystem and representing a nonlocal seed bank of potential colonizers. The third fraction contained Archaea that were always rare but actively growing; their affiliation and seasonal dynamics were similar to the abundant microbes and could not be considered a seed bank. We also showed that the major archaeal groups, Thaumarchaeota marine group I and Euryarchaeota group II.B in winter and Euryarchaeota group II.A in summer, contained different ecotypes with varying activities. Our findings suggest that archaeal diversity could be associated with distinct metabolisms or life strategies, and that the rare archaeal biosphere is composed of a complex assortment of organisms with distinct histories that affect their potential for growth. PMID:23536290

  19. Structure of the rare archaeal biosphere and seasonal dynamics of active ecotypes in surface coastal waters.

    PubMed

    Hugoni, Mylène; Taib, Najwa; Debroas, Didier; Domaizon, Isabelle; Jouan Dufournel, Isabelle; Bronner, Gisèle; Salter, Ian; Agogué, Hélène; Mary, Isabelle; Galand, Pierre E

    2013-04-01

    Marine Archaea are important players among microbial plankton and significantly contribute to biogeochemical cycles, but details regarding their community structure and long-term seasonal activity and dynamics remain largely unexplored. In this study, we monitored the interannual archaeal community composition of abundant and rare biospheres in northwestern Mediterranean Sea surface waters by pyrosequencing 16S rDNA and rRNA. A detailed analysis of the rare biosphere structure showed that the rare archaeal community was composed of three distinct fractions. One contained the rare Archaea that became abundant at different times within the same ecosystem; these cells were typically not dormant, and we hypothesize that they represent a local seed bank that is specific and essential for ecosystem functioning through cycling seasonal environmental conditions. The second fraction contained cells that were uncommon in public databases and not active, consisting of aliens to the studied ecosystem and representing a nonlocal seed bank of potential colonizers. The third fraction contained Archaea that were always rare but actively growing; their affiliation and seasonal dynamics were similar to the abundant microbes and could not be considered a seed bank. We also showed that the major archaeal groups, Thaumarchaeota marine group I and Euryarchaeota group II.B in winter and Euryarchaeota group II.A in summer, contained different ecotypes with varying activities. Our findings suggest that archaeal diversity could be associated with distinct metabolisms or life strategies, and that the rare archaeal biosphere is composed of a complex assortment of organisms with distinct histories that affect their potential for growth.

  20. Radionuclide Concentrations in Soils and Vegetation at Low-Level Radioactive Waste Disposal Area G during the 1997 Growing Season

    SciTech Connect

    L. Naranjo, Jr.; P. R. Fresquez; R. J. Wechsler

    1998-08-01

    Soil and overstory and understory vegetation (washed and unwashed) collected at eight locations within and around Area G-a low-level radioactive solid-waste disposal facility at Los Alamos National Laboratory-were analyzed for 3H, 238Pu, 239Pu, 137CS, 234U, 235U, 228AC, Be, 214Bi, 60Co, 40& 54Mn, 22Na, 214Pb and 208Tl. In general, most radionuclide concentrations, with the exception of 3Ef and ~9Pu, in soils and overstory and understory vegetation collected from within and around Area G were within upper (95'%) level background concentrations. Although 3H concentrations in vegetation from most sites were significantly higher than background (>2 pCi mL-l), concentrations decreased markedly in comparison to last year's results. The highest `H concentration in vegetation was detected from a juniper tree that was growing over tritium shaft /+150; it contained 530,000 pCi 3H mL-l. Also, as in the pas~ the transuranic waste pad area contained the highest levels of 239Pu in soils and in understory vegetation as compared to other areas at Area G.

  1. Altered resting-state activity in seasonal affective disorder.

    PubMed

    Abou Elseoud, Ahmed; Nissilä, Juuso; Liettu, Anu; Remes, Jukka; Jokelainen, Jari; Takala, Timo; Aunio, Antti; Starck, Tuomo; Nikkinen, Juha; Koponen, Hannu; Zang, Yu-Feng; Tervonen, Osmo; Timonen, Markku; Kiviniemi, Vesa

    2014-01-01

    At present, our knowledge about seasonal affective disorder (SAD) is based mainly up on clinical symptoms, epidemiology, behavioral characteristics and light therapy. Recently developed measures of resting-state functional brain activity might provide neurobiological markers of brain disorders. Studying functional brain activity in SAD could enhance our understanding of its nature and possible treatment strategies. Functional network connectivity (measured using ICA-dual regression), and amplitude of low-frequency fluctuations (ALFF) were measured in 45 antidepressant-free patients (39.78 ± 10.64, 30 ♀, 15 ♂) diagnosed with SAD and compared with age-, gender- and ethnicity-matched healthy controls (HCs) using resting-state functional magnetic resonance imaging. After correcting for Type 1 error at high model orders (inter-RSN correction), SAD patients showed significantly increased functional connectivity in 11 of the 47 identified RSNs. Increased functional connectivity involved RSNs such as visual, sensorimotor, and attentional networks. Moreover, our results revealed that SAD patients compared with HCs showed significant higher ALFF in the visual and right sensorimotor cortex. Abnormally altered functional activity detected in SAD supports previously reported attentional and psychomotor symptoms in patients suffering from SAD. Further studies, particularly under task conditions, are needed in order to specifically investigate cognitive deficits in SAD.

  2. Effect of corn dry distiller grains plus solubles supplementation level on performance and digestion characteristics of steers grazing native range during forage growing season.

    PubMed

    Martínez-Pérez, M F; Calderón-Mendoza, D; Islas, A; Encinias, A M; Loya-Olguín, F; Soto-Navarro, S A

    2013-03-01

    Two experiments were conducted to evaluate effects of corn dry distiller grains plus condensed solubles (DDGS) supplementation level on performance digestion characteristics of steers grazing native range during the forage growing season. In the performance study, 72 (206 ± 23.6 kg; 2008) and 60 (230 ± 11.3 kg; 2009) English crossbred steer calves were used in a randomized complete block design replicated over 2 yr. The grazing periods lasted 56 and 58 d and started on August 11 and 18 for 2008 and 2009, respectively. Each year, steers were blocked by BW (light, medium, and heavy), stratified by BW within blocks, and randomly assigned to 1 of 4 grazing groups. Each grazing group (6 steers in 2008 and 5 in 2009) was assigned to a DDGS supplementation levels (0, 0.2, 0.4, and 0.6% BW). Grazing group served as the experimental unit with 12 groups per year receiving 1 of 4 treatments for 2 yr (n = 6). In the metabolism study, 16 English crossbred steers (360 ± 28.9 kg) fitted with ruminal cannulas grazing native range during the summer growing season were used in a completely randomized design to evaluate treatment effects on forage intake and digestion. The experiment was conducted during the first and second weeks of October 2008. Steers were randomly assigned to supplement level (0, 0.2, 0.4, and 0.6% BW; n = 4) and grazed a single native range pasture with supplements offered individually once daily at 0700 h. In the performance study, ADG (0.64, 0.75, 0.80, and 0.86 ± 0.03 kg/d for 0, 0.2, 0.4, and 0.6% BW, respectively) increased linearly (P = 0.01) with increasing DDGS supplementation level. In the metabolism study, forage OM, NDF, CP, and ether extract (EE) intake decreased (P ≤ 0.05) linearly with increasing DDGS supplementation level. Total CP and EE intake increased (P ≤ 0.002) with increasing DDGS supplementation level. Digestibility of OM, NDF, and EE increased (linear; P ≤ 0.008) whereas the soluble CP fraction of forage masticate sample

  3. The contribution of soil biogenic NO and HONO emissions from a managed hyperarid ecosystem to the regional NOx emissions during growing season

    NASA Astrophysics Data System (ADS)

    Mamtimin, Buhalqem; Meixner, Franz X.; Behrendt, Thomas; Badawy, Moawad; Wagner, Thomas

    2016-08-01

    A study was carried out to understand the contributions of soil biogenic NO emissions from managed (fertilized and irrigated) hyperarid ecosystems in NW China to the regional NOx emissions during the growing season. Soil biogenic net potential NO fluxes were quantified by laboratory incubation of soil samples from the three dominating ecosystems (desert, cotton, and grape fields). Regional biogenic NO emissions were calculated bottom-up hourly for the entire growing season (April-September 2010) by considering corresponding land use, hourly data of soil temperature, gravimetric soil moisture, and fertilizer enhancement factors. The regional HONO emissions were estimated using the ratio of the optimum condition ((FN,opt(HONO) to FN,opt (NO)). Regional anthropogenic NOx emissions were calculated bottom-up from annual statistical data provided by regional and local government bureaus which have been downscaled to monthly value. Regional top-down emission estimates of NOx were derived on the monthly basis from satellite observations (OMI) of tropospheric vertical NO2 column densities and prescribed values of the tropospheric NOx lifetime. In order to compare the top-down and bottom-up emission estimates, all emission estimates were expressed in terms of mass of atomic nitrogen. Consequently, monthly top-down NOx emissions (total) were compared with monthly bottom-up NOx emissions (biogenic + anthropogenic) for the time of the satellite overpass (around 13:00 LT) with the consideration of the diurnal cycle of bottom-up estimates. Annual variation in total Tohsun Oasis NOx emissions is characterized by a strong peak in winter (December-February) and a secondary peak in summer (June-August). During summer, soil biogenic emissions were from equal to double that of related anthropogenic emissions, and grape soils were the main contributor to soil biogenic emissions, followed by cotton soils, while emissions from the desert were negligible. The top-down and bottom

  4. Deeper winter snow reduces ecosystem C losses but increases the global warming potential of Arctic tussock tundra over the growing season.

    NASA Astrophysics Data System (ADS)

    Blanc-Betes, E.; Welker, J. M.; Gomez-Casanovas, N.; Gonzalez-Meler, M. A.

    2015-12-01

    Arctic winter precipitation is projected to increase globally over the next decades, spatial variability encompassing areas with increases and decreases in winter snow. Changes in winter precipitation strongly affect C dynamics in Arctic systems and may lead to major positive climate forcing feedbacks. However, impacts of predicted changes in snowfall and accumulation on the rate and form of C fluxes (CO2 and CH4) and associated forcing feedbacks from Arctic tundra remain uncertain. We investigated how changes in winter precipitation affect net ecosystem CO2 and CH4 fluxes and budgets of moist acidic tundra in an 18-yrs snow fence experiment over a complete growing season at Toolik Lake, AK. Arctic tundra under ambient winter precipitation (CTL) was a net source of CO2 and CH4, yielding net C losses over the growing season. Reduced snow (-15-30% snow depth; RS) switched the system to a net CO2 sink mostly by limiting SOC decomposition within colder soils. Snow additions progressively reduced net ecosystem CO2 losses compared to CTL, switching the system into a weaker net CO2 source with medium additions (+20-45% snow depth; MS) and into a small net CO2 sink with high additions (+70-100% snow depth; HS). Increasingly wetter soils with snow additions constrained the temperature sensitivity of aerobic decomposition and favored the anaerobic metabolism, buffering ecosystem CO2 losses despite substantial soil warming. Accordingly, Arctic tundra switched from a sustained CH4 sink at RS site to an increasingly stronger CH4 source with snow additions. Accounting for both CO2 and CH4, the RS site became a net C sink over the growing season, overall reducing the global warming potential (CO2 equiv.; GWP) of the system relative to CTL. Snow additions progressively reduced net C losses at the MS site compared to CTL and the system transitioned into a net C sink at HS plots, partly due to the slower metabolism of anaerobic decomposition. However, given the greater radiative

  5. Isoprene emissions from downy oak under water limitation during an entire growing season: what cost for growth?

    PubMed

    Genard-Zielinski, Anne-Cyrielle; Ormeño, Elena; Boissard, Christophe; Fernandez, Catherine

    2014-01-01

    Increases in the production of terpene- and phenolic-like compounds in plant species under abiotic stress conditions have been interpreted in physiological studies as a supplementary defense system due to their capacity to limit cell oxidation. From an ecological perspective however, these increases are only expected to confer competitive advantages if they do not imply a significant cost for the plant, that is, growth reduction. We investigated shifts of isoprene emissions, and to a lesser extent phenolic compound concentration, of Quercus pubescens Willd. from early leaf development to leaf senescence under optimal watering (control: C), mild and severe water stress (MS, SS). The impact of water stress was concomitantly assessed on plant physiological (chlorophyll fluorescence, stomatal conductance, net photosynthesis, water potential) functional (relative leaf water content, leaf mass per area ratio) and growth (aerial and root biomass) traits. Growth changes allowed to estimate the eventual costs related to the production of isoprene and phenolics. The total phenolic content was not modified under water stress whereas isoprene emissions were promoted under MS over the entire growing cycle despite the decline of Pn by 35%. Under SS, isoprene emissions remained similar to C all over the study despite the decline of Pn by 47% and were thereby clearly uncoupled to Pn leading to an overestimation of the isoprene emission factor by 44%. Under SS, maintenance of isoprene emissions and phenolic compound concentration resulted in very significant costs for the plants as growth rates were very significantly reduced. Under MS, increases of isoprene emission and maintenance of phenolic compound concentration resulted in moderate growth reduction. Hence, it is likely that investment in isoprene emissions confers Q. pubescens an important competitive advantage during moderate but not severe periods of water scarcity. Consequences of this response for air quality in North

  6. Isoprene Emissions from Downy Oak under Water Limitation during an Entire Growing Season: What Cost for Growth?

    PubMed Central

    Genard-Zielinski, Anne-Cyrielle; Ormeño, Elena; Boissard, Christophe; Fernandez, Catherine

    2014-01-01

    Increases in the production of terpene- and phenolic-like compounds in plant species under abiotic stress conditions have been interpreted in physiological studies as a supplementary defense system due to their capacity to limit cell oxidation. From an ecological perspective however, these increases are only expected to confer competitive advantages if they do not imply a significant cost for the plant, that is, growth reduction. We investigated shifts of isoprene emissions, and to a lesser extent phenolic compound concentration, of Quercus pubescens Willd. from early leaf development to leaf senescence under optimal watering (control: C), mild and severe water stress (MS, SS). The impact of water stress was concomitantly assessed on plant physiological (chlorophyll fluorescence, stomatal conductance, net photosynthesis, water potential) functional (relative leaf water content, leaf mass per area ratio) and growth (aerial and root biomass) traits. Growth changes allowed to estimate the eventual costs related to the production of isoprene and phenolics. The total phenolic content was not modified under water stress whereas isoprene emissions were promoted under MS over the entire growing cycle despite the decline of Pn by 35%. Under SS, isoprene emissions remained similar to C all over the study despite the decline of Pn by 47% and were thereby clearly uncoupled to Pn leading to an overestimation of the isoprene emission factor by 44%. Under SS, maintenance of isoprene emissions and phenolic compound concentration resulted in very significant costs for the plants as growth rates were very significantly reduced. Under MS, increases of isoprene emission and maintenance of phenolic compound concentration resulted in moderate growth reduction. Hence, it is likely that investment in isoprene emissions confers Q. pubescens an important competitive advantage during moderate but not severe periods of water scarcity. Consequences of this response for air quality in North

  7. Isoprene emissions from downy oak under water limitation during an entire growing season: what cost for growth?

    PubMed

    Genard-Zielinski, Anne-Cyrielle; Ormeño, Elena; Boissard, Christophe; Fernandez, Catherine

    2014-01-01

    Increases in the production of terpene- and phenolic-like compounds in plant species under abiotic stress conditions have been interpreted in physiological studies as a supplementary defense system due to their capacity to limit cell oxidation. From an ecological perspective however, these increases are only expected to confer competitive advantages if they do not imply a significant cost for the plant, that is, growth reduction. We investigated shifts of isoprene emissions, and to a lesser extent phenolic compound concentration, of Quercus pubescens Willd. from early leaf development to leaf senescence under optimal watering (control: C), mild and severe water stress (MS, SS). The impact of water stress was concomitantly assessed on plant physiological (chlorophyll fluorescence, stomatal conductance, net photosynthesis, water potential) functional (relative leaf water content, leaf mass per area ratio) and growth (aerial and root biomass) traits. Growth changes allowed to estimate the eventual costs related to the production of isoprene and phenolics. The total phenolic content was not modified under water stress whereas isoprene emissions were promoted under MS over the entire growing cycle despite the decline of Pn by 35%. Under SS, isoprene emissions remained similar to C all over the study despite the decline of Pn by 47% and were thereby clearly uncoupled to Pn leading to an overestimation of the isoprene emission factor by 44%. Under SS, maintenance of isoprene emissions and phenolic compound concentration resulted in very significant costs for the plants as growth rates were very significantly reduced. Under MS, increases of isoprene emission and maintenance of phenolic compound concentration resulted in moderate growth reduction. Hence, it is likely that investment in isoprene emissions confers Q. pubescens an important competitive advantage during moderate but not severe periods of water scarcity. Consequences of this response for air quality in North

  8. Evaluation of the onset and length of growing season to define planting date—`a case study for Mali (West Africa)'

    NASA Astrophysics Data System (ADS)

    Akinseye, F. M.; Agele, S. O.; Traore, P. C. S.; Adam, M.; Whitbread, A. M.

    2016-05-01

    The agroecological zones (AEZ) of Mali fall within the semi-arid climate, the ability to determine efficiently or predict accurately the onset of growing season (OGS), and length of growing season (LGS) cannot be over-emphasized due to highly variable rainfall pattern and the dependence of smallholder farmers practising on rainfed farming agriculture. In this study, we determined the most suitable method for predicting the onset date of rainfall across AEZ that fitted with the planting windows of major cereal crops (maize, millet, and sorghum). Using long-term daily rainfall records from 22 meteorological stations spread across AEZ of Mali, four (4) known methods were applied to determine the onset dates of the rain. The mean onset dates were statistically compared with the farmer's planting window for the selected weather stations to determine the suitable dates of OGS and LGS. The hypothesis considered a time lag minimum of 7 days between the mean onset date and traditional farmer sowing dates for the crops. Then, the preferred method was used to estimate OGS based on early, normal and late dates respectively across the stations. Also, the estimated LGS according to each zone was evaluated using probability distribution chart with duration to maturity for varieties of the same crops. The results showed that Def_4 was found appropriate for Sahelian and Sudano-Sahelian zones; Def_3 satisfied the criteria and exhibited superior capacity into farmer's average planting date over Sudanian and Guinea Savannah zones. These results have an important application in cropping systems in order to prevent crop failure and ensure a better choice of crop variety according to LGS under climate variability and change being experienced across Mali.

  9. Ultra-high Resolution Carbon Isotope Records in Tree Rings: Indicators of Carbon Allocation and Growing Season Precipitation/Temperature (Invited)

    NASA Astrophysics Data System (ADS)

    Jahren, A.; Schubert, B.

    2010-12-01

    The rapidity and ease of carbon stable isotope measurements on organic substrates has opened the possibility of ultra-high resolution δ13C analyses within tree rings at < 30 to 100 micron increments. We present such measurements for 80 individual tree rings, from 10 trees spanning the last 55 million years in age from arctic, temperate, and tropical environments. Morphological features such as growth rings and resin canals were not preserved in some ancient specimens making identification of annual rings via standard techniques impossible. However, the annual patterns observed in ultra-high resolution δ13C records allowed for characterization of these unknown specimens as evergreen or deciduous. A combination of our data with that published in the literature showed a strong correlation between the amplitude of the δ13C pattern and growing season precipitation/temperature in > 90% of modern evergreen trees examined to date. Ultra-high resolution δ13C analyses of ancient, non-permineralized, evergreen trees could therefore provide quantitative estimates of past climate at annual or seasonal resolution.

  10. Beyond leaf color: Comparing camera-based phenological metrics with leaf biochemical, biophysical, and spectral properties throughout the growing season of a temperate deciduous forest

    NASA Astrophysics Data System (ADS)

    Yang, Xi; Tang, Jianwu; Mustard, John F.

    2014-03-01

    Plant phenology, a sensitive indicator of climate change, influences vegetation-atmosphere interactions by changing the carbon and water cycles from local to global scales. Camera-based phenological observations of the color changes of the vegetation canopy throughout the growing season have become popular in recent years. However, the linkages between camera phenological metrics and leaf biochemical, biophysical, and spectral properties are elusive. We measured key leaf properties including chlorophyll concentration and leaf reflectance on a weekly basis from June to November 2011 in a white oak forest on the island of Martha's Vineyard, Massachusetts, USA. Concurrently, we used a digital camera to automatically acquire daily pictures of the tree canopies. We found that there was a mismatch between the camera-based phenological metric for the canopy greenness (green chromatic coordinate, gcc) and the total chlorophyll and carotenoids concentration and leaf mass per area during late spring/early summer. The seasonal peak of gcc is approximately 20 days earlier than the peak of the total chlorophyll concentration. During the fall, both canopy and leaf redness were significantly correlated with the vegetation index for anthocyanin concentration, opening a new window to quantify vegetation senescence remotely. Satellite- and camera-based vegetation indices agreed well, suggesting that camera-based observations can be used as the ground validation for satellites. Using the high-temporal resolution dataset of leaf biochemical, biophysical, and spectral properties, our results show the strengths and potential uncertainties to use canopy color as the proxy of ecosystem functioning.

  11. Plasma membrane H(+) -ATPase gene expression, protein level and activity in growing and non-growing regions of barley (Hordeum vulgare) leaves.

    PubMed

    Visnovitz, Tamás; Solti, Adám; Csikós, György; Fricke, Wieland

    2012-04-01

    Plasma membrane proton ATPase (PM-H⁺-ATPase) is the key means through which plant cells energize nutrient uptake and acidify the apoplast. Both of these processes aid cell elongation; yet, it is not known how such a suspected role of the PM-H⁺-ATPase in growth is reflected through changes in its transcript level and activity in grass leaves. In the present study on leaf three of barley, the elongation zone and the emerged blade, which contained fully expanded cells were analyzed. Plasma membranes were isolated and used to assay the activity (ATPase assay) and abundance (western blotting) of PM-H⁺-ATPase protein. Expression of mRNA was quantified using real-time polymerase chain reaction (qPCR). PM-H⁺-ATPase transcript and protein level and activity differed little between growing and non-growing leaf regions when values were related to unit extracted total RNA and cell number, respectively. However, when values were related to unit surface area of plasma membrane, they were more than twice as high in growing compared with non-growing leaf tissue. It is concluded that this higher surface density of PM-H⁺-ATPase activity in growing barley leaf tissue aids apoplast acidification and cell expansion. PMID:22257033

  12. [Effects of growing time on Panax ginseng rhizosphere soil microbial activity and biomass].

    PubMed

    Xiao, Chun-ping; Yang, Li-min; Ma, Feng-min

    2014-12-01

    Using the field sampling and indoor soil cultivation methods, the dynamic of ginseng rhizosphere soil microbial activity and biomass with three cultivated ages was studied to provide a theory basis for illustrating mechanism of continuous cropping obstacles of ginseng. The results showed that ginseng rhizosphere soil microbial activity and biomass accumulation were inhibited observably by growing time. The soil respiration, soil cellulose decomposition and soil nitrification of ginseng rhizosphere soil microorganism were inhibited significantly (P <0.05), in contrast to the control soil uncultivated ginseng (R0). And the inhibition was gradual augmentation with the number of growing years. The soil microbial activity of 3a ginseng soil (R3) was the lowest, and its activity of soil respiration, soil cellulose decomposition, soil ammonification and soil nitrification was lower than that in R0 with 56.31%, 86.71% and 90. 53% , respectively. The soil ammonification of ginseng rhizosphere soil microbial was significantly promoted compared with R0. The promotion was improved during the early growing time, while the promotion was decreased with the number of growing years. The soil ammonification of R1, R2 and R3 were lower than that in R0 with 32.43%, 80.54% and 66.64% separately. The SMB-C and SMB-N in ginseng rhizosphere soil had a decreased tendency with the number of growing years. The SMB-C difference among 3 cultivated ages was significant, while the SMB-N was not. The SMB of R3 was the lowest. Compared with R0, the SMB-C and the SMB-N were significantly reduced 77.30% and 69.36%. It was considered by integrated analysis that the leading factor of continuous cropping obstacle in ginseng was the changes of the rhizosphere soil microbial species, number and activity as well as the micro-ecological imbalance of rhizosphere soil caused by the accumulation of ginseng rhizosphere secretions.

  13. Radionuclide concentrations in/on vegetation at radioactive-waste disposal Area G during the 1995 growing season. Progress report

    SciTech Connect

    Fresquez, P.R.; Vold, E.L.; Naranjo, L. Jr.

    1996-03-01

    Overstory (pinon pine) and understory (grass and forb) vegetation were collected within and around selected points at Area G--a low- level radioactive solid-waste disposal facility at Los Alamos National Laboratory--for the analysis of tritium ({sup 3}H), strontium ({sup 90}Sr), plutonium ({sup 238}Pu and {sup 239}Pu), cesium ({sup 137}Cs), and total uranium. Also, heavy metals (Ag, As, Ba, Be, Cd, Cr, Hg, Ni, Pb, Sb, Se, and Tl) in/on vegetation were determined. In general, most (unwashed) vegetation collected within and around Area G contained {sup 3}H, uranium, {sup 238}Pu, and {sup 239}Pu in higher concentrations than vegetation collected from background areas. Tritium, in particular, was detected as high as 7300 pCi mL{sup -1} in understory vegetation collected from the west side of the transuranic (TRU) pads. The south and west ends of the tritium shaft field also contained elevated levels of {sup 3}H in overstory, and especially in understory vegetation, as compared to background; this suggests that {sup 3}H may be migrating from this waste repository through surface and subsurface pathways. Also, understory vegetation collected north of the TRU pads (adjacent to the fence line of Area G) contained the highest values of {sup 238}Pu and {sup 239}Pu as compared to background, and may be a result of surface holding, storage, and/or disposal activities.

  14. A complete and continuous pesticide screening during one growing season in five small Swiss rivers with agricultural watersheds

    NASA Astrophysics Data System (ADS)

    Mangold, Simon; Comte, Rahel; Doppler, Tobias; Wittmer, Irene; Moschet, Christoph; Stamm, Christian; Singer, Heinz; Kunz, Manuel

    2016-04-01

    Agricultural pesticides are regularly found in surface waters at concentration levels that raise ecotoxicological concerns. Due to large fluctuations in concentration over time and the potentially high number of pesticides in agricultural watersheds, it is difficult to obtain a comprehensive overview of the actual pollution level. This collaborative project between research and Swiss federal and cantonal authorities aimed for a comprehensive analysis of pesticide pollution in five small agricultural streams to address this knowledge gap. The five rivers are located in catchments (1.5 to 9 km2) with intensive agriculture covering a wide range of crops, such as grains, vegetables, vineyards and orchards. Urban activities and influences are low. Twelve-hour composite samples were collected continuously from March until the end of August with automatic sampling devices, resulting in 360 samples per site. Using precipitation and water level data, we differentiated between discharge events and low-flow periods. Samples taken during dry weather were pooled for the analysis. This procedure resulted in a complete concentration profile over the entire monitoring period covered by 60 samples per site. The analysis, using liquid chromatography coupled to high resolution mass spectrometry (Orbitrap technology), involved a target screening of 248 pesticides including fungicides, herbicides, insecticides, as well as important transformation products. Data on the total number and distribution of pesticides, their detection frequency, crop specific applications and concentration time profiles will be presented. Preliminary results indicate substantial pesticide exposure since at least 20 different compounds were detected in all samples. One sample even contained a mixture of 80 pesticides. The majority of concentrations were in the low ng/L range but concentrations of a few compounds were very high (several micrograms/L) during discharge events as well as during low flow conditions

  15. Reproductive phenology of the American Bullfrog in subtropical Brazil: photoperiod as a main determinant of seasonal activity.

    PubMed

    Medeiros, Camila I; Both, Camila; Kaefer, Igor L; Cechin, Sonia Z

    2016-07-11

    The North American bullfrog Lithobates catesbeianus continues to invade ecosystems worldwide, potentially causing population declines and even extinctions. Within its native distribution, bullfrogs show prolonged reproductive seasons and high fertility. However, data on breeding biology of bullfrogs ex-situ in invaded localities mainly comes from anecdotal reports. Understanding how invasive species are adjusting their life histories to new colonized environments is important for conservation purposes. Here we describe temporal and spatial abundance, calling activity, spawning and tadpole distribution of bullfrogs in southern Brazil. Eighteen samplings occurred during one year. The abundance of individuals was positively related to longer photoperiods and higher temperatures. Reproductive activity was also positively associated with longer photoperiods. Calling sites, spawning and tadpoles were associated with microhabitats presenting hydrophytes, which may provide shelter and thermal stability to bullfrogs. The reproductive seasonal activity of bullfrogs can be highly variable across its growing geographical range, but in subtropical Brazil it is associated with photoperiod, a highly predictable abiotic determinant. In our study area, bullfrogs presented a breeding season twice as long as that observed in some native localities. We suggest that management strategies directed to bullfrog populations must consider the habitat structures and seasonal regimes determined by each invaded environment. PMID:27411069

  16. Reproductive phenology of the American Bullfrog in subtropical Brazil: photoperiod as a main determinant of seasonal activity.

    PubMed

    Medeiros, Camila I; Both, Camila; Kaefer, Igor L; Cechin, Sonia Z

    2016-07-11

    The North American bullfrog Lithobates catesbeianus continues to invade ecosystems worldwide, potentially causing population declines and even extinctions. Within its native distribution, bullfrogs show prolonged reproductive seasons and high fertility. However, data on breeding biology of bullfrogs ex-situ in invaded localities mainly comes from anecdotal reports. Understanding how invasive species are adjusting their life histories to new colonized environments is important for conservation purposes. Here we describe temporal and spatial abundance, calling activity, spawning and tadpole distribution of bullfrogs in southern Brazil. Eighteen samplings occurred during one year. The abundance of individuals was positively related to longer photoperiods and higher temperatures. Reproductive activity was also positively associated with longer photoperiods. Calling sites, spawning and tadpoles were associated with microhabitats presenting hydrophytes, which may provide shelter and thermal stability to bullfrogs. The reproductive seasonal activity of bullfrogs can be highly variable across its growing geographical range, but in subtropical Brazil it is associated with photoperiod, a highly predictable abiotic determinant. In our study area, bullfrogs presented a breeding season twice as long as that observed in some native localities. We suggest that management strategies directed to bullfrog populations must consider the habitat structures and seasonal regimes determined by each invaded environment.

  17. Seasonal effects on intestinal enzyme activity in the Australian agamid lizard, Lophognathus temporalis.

    PubMed

    Iglesias, Sebastian; Tracy, Christopher R; Bedford, Gavin S; McWhorter, Todd J; Christian, Keith A

    2009-05-01

    The tropical agamid lizard, Lophognathus temporalis, has higher metabolic and feeding rates during the wet season compared to the dry season. Also, lizards from urban sites tend to be larger than those from natural sites, partly due to site differences in food availability. Therefore, we hypothesized that activity of membrane-bound intestinal enzymes and masses of organs related to digestion would differ both seasonally and between urban and natural sites. To test this, we measured activities of aminopeptidase-N (APN), maltase, and sucrase, as well as organ masses. APN activity (micromol min(-1) g(-1)) was highest in the middle portion of the intestine (section 2), followed by the proximal portion (section 1) and then the distal portion (section 3). Maltase activity was highest in section 1 and decreased distally. We detected some sucrase activity in section 1 but none in sections 2 or 3. We found similar enzyme activities within each section irrespective of site or season. However, total enzyme activities were higher during the wet season compared to the dry season for both urban and bush L. temporalis. Total wet season enzyme activity in urban and bush L. temporalis was greatest for APN (25.4; 15.8 micromol min(-1); respectively), then maltase (3.9; 3.6 micromol min(-1); respectively) and then sucrase (0.3; 0.2 micromol min(-1); respectively). The higher total enzyme activities was the result of an increase in intestinal mass during the wet season.

  18. Cold Season Ground Validation Activities in support of GPM

    NASA Astrophysics Data System (ADS)

    Hudak, D. R.; Petersen, W. A.

    2012-12-01

    A fundamental component of the next-generation global precipitation data products that will be addressed by the GPM mission is the hydrologic cycle at higher latitudes. In this respect, falling snow represents a primary contribution to regional atmospheric and terrestrial water budgets. The current study provides provide information on the precipitation microphysics and processes associated with cold season precipitation and precipitating cloud systems across multiple scales. It also addresses the ability of in-situ ground-based sensors as well as multi-frequency active and passive microwave sensors to detect and estimate falling snow, and more generally to contribute to our knowledge and understanding of the complete global water cycle. The work supports the incorporation of appropriate physics into GPM snowfall retrieval algorithms and the development of improved ground validation techniques for GPM product evaluation. Important information for developing GPM falling snow retrieval algorithms will be provided by a field campaign that took place in the winter of 2011/12 in the Great Lakes area of North America, termed the GPM Cold Season Precipitation Experiment (GCPEx). GCPEx represented a collaboration among the NASA, Environment Canada (EC), the Canadian Space Agency and several US, Canadian and European universities. The data collection strategy for GCPEx was coordinated, stacked high-altitude and in-situ cloud aircraft missions sampling within a broader network of ground-based volumetric observations and measurements. The NASA DSC-8 research aircraft provided a platform for the downward-viewing dual-frequency radar and multi-frequency radiometer observations. The University of North Dakota Citation and the Canadian NRC Convair-580 aircraft provided in-situ profiles of cloud and precipitation microphysics using a suite of optical array probes and bulk measurement instrumentation. Ground sampling was focused about a densely-instrumented central location that is

  19. Make Summer Your Growing Season.

    ERIC Educational Resources Information Center

    Simons, Harriet

    1982-01-01

    Describes the opportunities available in summer workshops and graduate programs for music teachers. The impact of the workshops and programs on improving teacher effectiveness is evaluated. Criteria are included for evaluating program offerings for their usefulness to teachers. The author offers suggestions to workshop planners to improve the…

  20. Monitoring of a fast-growing speleothem site from the Han-sur-Lesse cave, Belgium, indicates equilibrium deposition of the seasonal δ18O and δ13C signals in the calcite

    NASA Astrophysics Data System (ADS)

    Van Rampelbergh, M.; Verheyden, S.; Allan, M.; Quinif, Y.; Keppens, E.; Claeys, P.

    2014-10-01

    values. The cave system varies seasonally in response to the activity of the vegetation cover and outside air temperature between a "summer mode" lasting from June to December and a "winter mode" from December to June. The low δ18O and high δ13C values of the darker speleothem layers indicate that they are formed during summer, while light layers are formed during winter. The darker the color of a layer, the more compact its calcite structure is, and the more negative its δ18O signal and the more positive its δ13C signal are. Darker layers deposited from summer drip water affected by PCP are suggested to contain lower Ca2+ concentration. If indeed the calcite saturation represents the main factor driving the Proserpine growth rate, the dark layers should grow slower than the white layers.

  1. Observations of the northern seasonal polar cap on Mars: I. Spring sublimation activity and processes

    USGS Publications Warehouse

    Hansen, C.J.; Byrne, S.; Portyankina, G.; Bourke, M.; Dundas, C.; McEwen, A.; Mellon, M.; Pommerol, A.; Thomas, N.

    2013-01-01

    Spring sublimation of the seasonal CO2 northern polar cap is a dynamic process in the current Mars climate. Phenomena include dark fans of dune material propelled out onto the seasonal ice layer, polygonal cracks in the seasonal ice, sand flow down slipfaces, and outbreaks of gas and sand around the dune margins. These phenomena are concentrated on the north polar erg that encircles the northern residual polar cap. The Mars Reconnaissance Orbiter has been in orbit for three Mars years, allowing us to observe three northern spring seasons. Activity is consistent with and well described by the Kieffer model of basal sublimation of the seasonal layer of ice applied originally in the southern hemisphere. Three typical weak spots have been identified on the dunes for escape of gas sublimed from the bottom of the seasonal ice layer: the crest of the dune, the interface of the dune with the interdune substrate, and through polygonal cracks in the ice. Pressurized gas flows through these vents and carries out material entrained from the dune. Furrows in the dunes channel gas to outbreak points and may be the northern equivalent of southern radially-organized channels (“araneiform” terrain), albeit not permanent. Properties of the seasonal CO2 ice layer are derived from timing of seasonal events such as when final sublimation occurs. Modification of dune morphology shows that landscape evolution is occurring on Mars today, driven by seasonal activity associated with sublimation of the seasonal CO2 polar cap.

  2. Spatio-temporal distribution of the timing of start and end of growing season along vertical and horizontal gradients in Japan.

    PubMed

    Nagai, Shin; Saitoh, Taku M; Nasahara, Kenlo Nishida; Suzuki, Rikie

    2015-01-01

    We detected the spatio-temporal variability in the timing of start (SGS) and end of growing season (EGS) in Japan from 2003 to 2012 by analyzing satellite-observed daily green-red vegetation index with a 500-m spatial resolution. We also examined the characteristics of SGS and EGS timing in deciduous broadleaf and needleleaf forests along vertical and horizontal gradients and then evaluated the relationship between their timing and daily mean air temperature. We found that for the timing of SGS and EGS, changes along the vertical gradient in deciduous broadleaf forest tended to be larger than those in deciduous needleleaf forest. For both forest types, changes along the vertical and horizontal gradients in the timing of EGS tended to be smaller than those of SGS. Finally, in both forest types, the sensitivity of the timing of EGS to air temperature was much less than that of SGS. These results suggest that the spatio-temporal variability in the timing of SGS and EGS detected by satellite data, which may be correlated with leaf traits, photosynthetic capacity, and environment conditions, provide useful ground-truthing information along vertical and horizontal gradients.

  3. Effect of storage on the content of polyphenols of minimally processed skin-on apple wedges from ten cultivars and two growing seasons.

    PubMed

    Rössle, Christian; Wijngaard, Hilde H; Gormley, Ronan T; Butler, Francis; Brunton, Nigel

    2010-02-10

    In this study, the polyphenolic composition of skin-on apple wedges from ten cultivars was examined during chill storage and over two growing seasons. Individual polyphenol compounds were measured using HPLC resulting in the total polyphenolic index (TPI). Total phenolic content (TPC) was quantified using the Folin-Ciocalteu assay. Chilled storage had a significant effect (P < 0.001) on the polyphenol composition of all ten cultivars grown in 2007 and 2008. Total phenolic indices (sum of individual polyphenols) and TPCs of nine of the ten cultivars significantly decreased (P < 0.001) after 5 days of storage at 2-4 degrees C. These indices increased in case of Shampion apples over the same storage period. Changes in the most abundant compounds (-)-epicatechin, procyanidins and chlorogenic acid were largely responsible for changes in overall TPI. Percentage loss was higher for compounds such as phloridzin with a degradation of up to 100%. Irrespective of the different starting level of specific polyphenols in each year; storage resulted in a similar percentage loss/gain for each cultivar.

  4. The application Of Fourier Prediction Models To Schedule Paddy Growing Season With High Resolution For Upgrading Farm Capacity Building (Case Study in Indramayu Regency)

    NASA Astrophysics Data System (ADS)

    Martuani Siregar, Plato

    2016-08-01

    Indonesian government still has obstacles in the production of annual paddy harvest and planting which causes a decrease 20 percent drop in National production. The failure of one of them caused by weather patterns and climate change that makes farmers difficult to plan future activities with good crop calender. That is because the coming of the rainy season at this moment cannot be predicted precisely. To that end, the role of technology in model and estimate the precise rainfall (high resolution) becomes very important. The developing Fourier prediction models to become agriculture information system was user friendly for instructor/extension officers and farmers who can overcome this problem. The agriculture information models are developed to determine the time of crop calendar weighted maps with rice terraces whom government services, scout and farmers at Indramayu regency easily wears it. The sum of sinus models is used alternatively to predict deciles futures and monthly rainfalls for one year ahead produce a 0.97 correlation with the observed data in Indramayu region. The residue of the sum of sinus models became anomalous rainfall for instan ENSO can cause forward and late in rainfall season. Basically by using a method of curve fitting Sum of Sine results turned out to be related to the monsoon event and climate classification that indicate to distribute annual. While residue model shows cycles of 28.89,61.79 and 80.9 months. These frequencies are related to ENSO event. The Schmidt & Ferguson climate classification of rainfalls and wind monthly conclude Indramayu Regency dominate by type of wet and dry monthly. Map early in the season prediction and map early the planting of rice that have been tested since the start built 2008 is currently being updated with a system software, so that will make it easier for farmers and extension officers as well as related service to apply it on crop calendar.

  5. Seasonal variation in metabolic rate, flight activity and body size of Anopheles gambiae in the Sahel

    PubMed Central

    Huestis, Diana L.; Yaro, Alpha S.; Traoré, Adama I.; Dieter, Kathryne L.; Nwagbara, Juliette I.; Bowie, Aleah C.; Adamou, Abdoulaye; Kassogué, Yaya; Diallo, Moussa; Timbiné, Seydou; Dao, Adama; Lehmann, Tovi

    2012-01-01

    SUMMARY Malaria in Africa is vectored primarily by the Anopheles gambiae complex. Although the mechanisms of population persistence during the dry season are not yet known, targeting dry season mosquitoes could provide opportunities for vector control. In the Sahel, it appears likely that M-form A. gambiae survive by aestivation (entering a dormant state). To assess the role of eco-physiological changes associated with dry season survival, we measured body size, flight activity and metabolic rate of wild-caught mosquitoes throughout 1 year in a Sahelian locality, far from permanent water sources, and at a riparian location adjacent to the Niger River. We found significant seasonal variation in body size at both the Sahelian and riparian sites, although the magnitude of the variation was greater in the Sahel. For flight activity, significant seasonality was only observed in the Sahel, with increased flight activity in the wet season when compared with that just prior to and throughout the dry season. Whole-organism metabolic rate was affected by numerous biotic and abiotic factors, and a significant seasonal component was found at both locations. However, assay temperature accounted completely for seasonality at the riparian location, while significant seasonal variation remained after accounting for all measured variables in the Sahel. Interestingly, we did not find that mean metabolic rate was lowest during the dry season at either location, contrary to our expectation that mosquitoes would conserve energy and increase longevity by reducing metabolism during this time. These results indicate that mosquitoes may use mechanisms besides reduced metabolic rate to enable survival during the Sahelian dry season. PMID:22623189

  6. Seasonal and Daily Variation in Physical Activity among Three-Year-Old Finnish Preschool Children

    ERIC Educational Resources Information Center

    Soini, Anne; Tammelin, Tuija; Sääkslahti, Arja; Watt, Anthony; Villberg, Jari; Kettunen, Tarja; Mehtälä, Anette; Poskiparta, Marita

    2014-01-01

    The purposes of this study were to assess seasonal, daily, and gender variations in children's physical activity (PA). ActiGraph GT3X accelerometers were used to record the three-year-old children's PA levels for five consecutive days in autumn and winter. Complete data for both seasons were obtained for 47 children. Despite a…

  7. Integrating multiscale polar active contours and region growing for microcalcifications segmentation in mammography

    NASA Astrophysics Data System (ADS)

    Arikidis, N. S.; Karahaliou, A.; Skiadopoulos, S.; Likaki, E.; Panagiotakis, G.; Costaridou, L.

    2009-07-01

    Morphology of individual microcalcifications is an important clinical factor in microcalcification clusters diagnosis. Accurate segmentation remains a difficult task due to microcalcifications small size, low contrast, fuzzy nature and low distinguishability from surrounding tissue. A novel application of active rays (polar transformed active contours) on B-spline wavelet representation is employed, to provide initial estimates of microcalcification boundary. Then, a region growing method is used with pixel aggregation constrained by the microcalcification boundary estimates, to obtain the final microcalcification boundary. The method was tested on dataset of 49 microcalcification clusters (30 benign, 19 malignant), originating from the DDSM database. An observer study was conducted to evaluate segmentation accuracy of the proposed method, on a 5-point rating scale (from 5:excellent to 1:very poor). The average accuracy rating was 3.98±0.81 when multiscale active rays were combined to region growing and 2.93±0.92 when combined to linear polynomial fitting, while the difference in rating of segmentation accuracy was statistically significant (p < 0.05).

  8. Proliferative activity of endotheliocytes of growing capillaries of the rabbit cornea

    SciTech Connect

    Gurina, O.Yu.; Mamontov, S.G.; Banin, V.V.

    1987-10-01

    The authors studied the intensity of DNA synthesis by cells of newly formed capillaries, growing in the rabbit cornea, after infliction of a silver nitrate burn and local application of colchicine. The intensity of capillary growth was investigated during stimulation and a combination of the burn with colchicine. Changes in activity of DNA synthesis by the endotheliocytes of newly formed capillaries during exposure throughout growth were also investigated. The intensity of cell proliferation was studied by measuring the incorporation of tritium-labelled thymidine into the endotheoiocyte nuclei.

  9. Rate of Nitrogen Application during the Growing Season and Spraying Plants with Urea in the Autumn Alters Uptake of other Nutrients by Deciduous and Evergreen Container-Grown Rhododendron

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The influence of N rate during the growing season and spraying plants with urea in the autumn on the uptake of other nutrients was assessed using container-grown rhododendron (Rhododendron 'H-1 P.J.M') and azalea (Rhododendron 'Cannon’s Double'). Plants were grown with a complete fertilizer containi...

  10. Growing up Active: A Study into Physical Activity in Long Day Care Centers

    ERIC Educational Resources Information Center

    Cashmore, Aaron W.; Jones, Sandra C.

    2008-01-01

    The child care center is an ideal setting in which to implement strategies to promote physical activity and healthy weight, but there is a paucity of empirical evidence on factors that influence physical activity in these settings. The current study gathered initial qualitative data to explore these factors. Child care workers from five long day…

  11. Influence of organic and conventional growing conditions on the nutrient contents of white head cabbage (Brassica oleracea var. capitata) during two successive seasons.

    PubMed

    Citak, Sedat; Sonmez, Sahriye

    2010-02-10

    Organically and conventionally grown white head cabbage (Brassica oleracea var. capitata) plants were cultivated during two successive seasons (spring and autumn) to evaluate the effects of the applications on the nutrient content of the edible part of cabbage plants. Seventeen different organic applications containing farmyard manure (FM), chicken manure (CM), and blood meal (BM) and 1 chemical fertilizer and 1 control, collectively 19 treatments, were examined under the open-field conditions. Recommendations of the best results obtained should be divided into groups in the following order regarding the mineral contents and also the seasons: 0.6 BM + 7.5 FM in the spring season, and 3.5 CM in the autumn season for N, P, and K content of cabbage. For Ca and Mg, the group division should be 1.7 CM + 0.6 BM in the spring season and 10.0 FM + 1.2 CM in the autumn season. The optimum recommendations for the micronutrients could be 5.0 FM + 1.0 BM in the spring season and 0.9 BM + 0.85 CM in the autumn season for Fe and Cu and 15.0 FM in the spring season, and 10.0 FM + 0.4 BM in the autumn season for Mn and Zn. FM and CM could be used in high rates in producing organic cabbage and could be substituted for chemical fertilizer especially in the spring season.

  12. Antimicrobial and antioxidant activities of essential oils of Satureja thymbra growing wild in Libya.

    PubMed

    Giweli, Abdulhmid; Džamić, Ana M; Soković, Marina; Ristić, Mihailo S; Marin, Petar D

    2012-01-01

    The composition of essential oil isolated from Satureja thymbra, growing wild in Libya, was analyzed by GC and GC-MS. The essential oil was characterized by γ-terpinene (39.23%), thymol (25.16%), p-cymene (7.17%) and carvacrol (4.18%) as the major constituents. Antioxidant activity was analyzed using the 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical scavenging method. It possessed strong antioxidant activity (IC50 = 0.0967 mg/mL). The essential oil was also screened for its antimicrobial activity against eight bacterial and eight fungal species, showing excellent antimicrobial activity against the microorganisms used, in particular against the fungi. The oil of S. thymbra showed bacteriostatic activity at 0.001-0.1 mg/mL and was bactericidal at 0.002-0.2 mg/mL; fungistatic effects at 0.001-0.025 mg/mL and fungicidal effects at 0.001-0.1 mg/mL. The main constituents thymol, carvacrol and γ-terpinene also showed strong antimicrobial activity. The commercial fungicide bifonazole showed much lower antifungal activity than the tested oil. PMID:22538487

  13. Fusarium species and fumonisins associated with maize kernels produced in Rio Grande do Sul State for the 2008/09 and 2009/10 growing seasons

    PubMed Central

    Stumpf, R.; dos Santos, J.; Gomes, L.B.; Silva, C.N.; Tessmann, D.J.; Ferreira, F.D.; Machinski, M.; Del Ponte, E.M.

    2013-01-01

    Ear rots caused by Fusarium spp. are among the main fungal diseases that contribute to poor quality and the contamination of maize grains with mycotoxins. This study aimed to determine the visual incidence of fungal-damaged kernels (FDKs), the incidence of two main Gibberella (a teleomorph of Fusarium) complexes (G. fujikuroi and G. zeae) associated with maize using a seed health blotter test, and the fumonisin levels, using high performance liquid chromatography, in samples of maize grains grown across 23 municipalities during the 2008/09 and 2009/10 growing seasons. Additionally, 104 strains that were representative of all of the analysed samples were identified to species using PCR assays. The mean FDK was seven per cent, and only six of the samples had levels greater than six per cent. Fusarium spp. of the G. fujikuroi complex were present in 96% of the samples, and G. zeae was present in 18% of the samples (5/27). The mean incidence of G. fujikuroi was 58%, and the incidence of G. zeae varied from 2 to 6%. FB1 was found in 58.6%, FB2 in 37.9%, and both toxins in 37.9% of the samples. The FB1 and FB2 levels were below the quantification limits for 41.3% of the samples, and the mean FB1 levels (0.66 μg/g) were higher than the mean FB2 levels (0.42 μg/g). The PCR identification separated the 104 isolates into three of the G. fujikuroi complex: F. verticillioides (76%), F. subglutinans (4%) and F. proliferatum (2%); and G. zeae (anamorph = F. graminearum) (18%). Our results confirmed the dominance of F. verticillioides, similar to other regions of Brazil, but they differed due to the relatively higher incidence of F. graminearum. Total fumonisin levels were below the maximum limit determined by current Brazilian regulations. PMID:24159288

  14. Fusarium species and fumonisins associated with maize kernels produced in Rio Grande do Sul State for the 2008/09 and 2009/10 growing seasons.

    PubMed

    Stumpf, R; Dos Santos, J; Gomes, L B; Silva, C N; Tessmann, D J; Ferreira, F D; Machinski, M; Del Ponte, E M

    2013-05-31

    Ear rots caused by Fusarium spp. are among the main fungal diseases that contribute to poor quality and the contamination of maize grains with mycotoxins. This study aimed to determine the visual incidence of fungal-damaged kernels (FDKs), the incidence of two main Gibberella (a teleomorph of Fusarium) complexes (G. fujikuroi and G. zeae) associated with maize using a seed health blotter test, and the fumonisin levels, using high performance liquid chromatography, in samples of maize grains grown across 23 municipalities during the 2008/09 and 2009/10 growing seasons. Additionally, 104 strains that were representative of all of the analysed samples were identified to species using PCR assays. The mean FDK was seven per cent, and only six of the samples had levels greater than six per cent. Fusarium spp. of the G. fujikuroi complex were present in 96% of the samples, and G. zeae was present in 18% of the samples (5/27). The mean incidence of G. fujikuroi was 58%, and the incidence of G. zeae varied from 2 to 6%. FB1 was found in 58.6%, FB2 in 37.9%, and both toxins in 37.9% of the samples. The FB1 and FB2 levels were below the quantification limits for 41.3% of the samples, and the mean FB1 levels (0.66 μg/g) were higher than the mean FB2 levels (0.42 μg/g). The PCR identification separated the 104 isolates into three of the G. fujikuroi complex: F. verticillioides (76%), F. subglutinans (4%) and F. proliferatum (2%); and G. zeae (anamorph = F. graminearum) (18%). Our results confirmed the dominance of F. verticillioides, similar to other regions of Brazil, but they differed due to the relatively higher incidence of F. graminearum. Total fumonisin levels were below the maximum limit determined by current Brazilian regulations.

  15. The impact of growing-season length variability on carbon assimilation and evapotranspiration over 88 years in the eastern US deciduous forest

    PubMed

    White; Running; Thornton

    1999-02-01

    Recent research suggests that increases in growing-season length (GSL) in mid-northern latitudes may be partially responsible for increased forest growth and carbon sequestration. We used the BIOME-BGC ecosystem model to investigate the impacts of including a dynamically regulated GSL on simulated carbon and water balance over a historical 88-year record (1900-1987) for 12 sites in the eastern USA deciduous broadleaf forest. For individual sites, the predicted GSL regularly varied by more than 15 days. When grouped into three climatic zones, GSL variability was still large and rapid. There is a recent trend in colder, northern sites toward a longer GSL, but not in moderate and warm climates. The results show that, for all sites, prediction of a long GSL versus using the mean GSL increased net ecosystem production (NEP), gross primary production (GPP), and evapotranspiration (ET); conversely a short GSL is predicted to decrease these parameters. On an absolute basis, differences in GPP between the dynamic and mean GSL simulations were larger than the differences in NEP. As a percentage difference, though, NEP was much more sensitive to changes in GSL than were either GPP or ET. On average, a 1-day change in GSL changed NEP by 1.6%, GPP by 0.5%, and ET by 0.2%. Predictions of NEP and GPP in cold climates were more sensitive to changes in GSL than were predictions in warm climates. ET was not similarly sensitive. First, our results strongly agree with field measurements showing a high correlation between NEP and dates of spring growth, and second they suggest that persistent increases in GSL may lead to long-term increases in carbon storage.

  16. Projections of the advance in the start of the growing season during the 21st century based on CMIP5 simulations

    NASA Astrophysics Data System (ADS)

    Xia, Jiangjiang; Yan, Zhongwei; Jia, Gensuo; Zeng, Heqing; Jones, Philip Douglas; Zhou, Wen; Zhang, Anzhi

    2015-06-01

    It is well-known that global warming due to anthropogenic atmospheric greenhouse effects advanced the start of the vegetation growing season (SOS) across the globe during the 20th century. Projections of further changes in the SOS for the 21st century under certain emissions scenarios (Representative Concentration Pathways, RCPs) are useful for improving understanding of the consequences of global warming. In this study, we first evaluate a linear relationship between the SOS (defined using the normalized difference vegetation index) and the April temperature for most land areas of the Northern Hemisphere for 1982-2008. Based on this relationship and the ensemble projection of April temperature under RCPs from the latest state-of-the-art global coupled climate models, we show the possible changes in the SOS for most of the land areas of the Northern Hemisphere during the 21st century. By around 2040-59, the SOS will have advanced by -4.7 days under RCP2.6, -8.4 days under RCP4.5, and -10.1 days under RCP8.5, relative to 1985-2004. By 2080-99, it will have advanced by -4.3 days under RCP2.6, -11.3 days under RCP4.5, and -21.6 days under RCP8.5. The geographic pattern of SOS advance is considerably dependent on that of the temperature sensitivity of the SOS. The larger the temperature sensitivity, the larger the date-shift-rate of the SOS.

  17. Preliminary Study on Norovirus, Hepatitis A Virus, Escherichia coli and their Potential Seasonality in Shellfish from Different Growing and Harvesting Areas in Sardinia Region

    PubMed Central

    Fattaccio, Maria Caterina; Salza, Sara; Canu, Antonella; Marongiu, Edoardo; Pisanu, Margherita

    2014-01-01

    Edible lamellibranch molluscs can be involved in foodborne disease and infections of varying severity. They are filter feeding animals able to retain and concentrate in their organism bacteria, parasites, viruses and biotoxins marine algae present in their external environment. Major shellfish harvesting and relaying areas from different areas in Sardinia region were defined and studied by analysing different physicochemical parameters in the water and the levels of Escherichia coli (E. coli), Norovirus (NoVs) genogroup I (NoVGI), NoVs genogroup II (NoVGII) and hepatitis A virus (HAV) in the shellfish harvested and farmed from 2009 to 2011. During that period the identification of the viral agents was carried out by one step real-time reverse transcriptase-polymerase chain reaction and Escherichia coli according to ISO TS 16649-3:2005 standard method. A total of 1266 shellfish samples were tested for NoVGI, NoVGII, HAV and faecal indicators. Norovirus contamination was found in 337 samples (26.6%); only one sample of mussels was positive for HAV (0.08%); while E. coli prevalence was 3.8% in shellfish. The probability of observing shellfish samples positive for NoVs, HAV and E. coli presence was associated with harvesting, growing and relaying areas, period of sampling, environmental parameters, animal species (P<0.05). Although the higher prevalence rate of human enteropathogenic viruses was found in the winter period, we did not observe a significant relationship between the effect of seawater temperature (seasonality) and NoVs presence all over the study period; in fact, according to statistical analysis, the presence of human enteric viruses does not appear to be related to water temperature. PMID:27800328

  18. Phenotypic diversity and amylolytic activity of fast growing rhizobia from pigeonpea [Cajanus cajan (L.) Millsp].

    PubMed

    Júnior, Paulo Ivan Fernandes; de Lima, Andréa Aparecida; Passos, Samuel Ribeiro; Tuão Gava, Carlos Alberto; de Oliveira, Paulo Jansen; Rumjanek, Norma Gouvêa; Xavier, Gustavo Ribeiro

    2012-10-01

    This study evaluated 26 pigeonpea rhizobial isolates according to their cultural characteristics, intrinsic antibiotic resistance, salt and temperature tolerance, carbon source utilization and amylolytic activity. The cultural characterization showed that the majority of them presented the ability to acidify the YMA. Among the 27 isolates evaluated, 25 were able to grow when incubated at 42° C and 11 showed tolerance to 3% (w/v) of NaCl in YMA medium. The patterns of carbon sources utilization was very diverse among the isolates. It was observed the capacity of three strains to metabolize all the carbon sources evaluated and a total of 42% of the bacterial isolates was able to grow in the culture medium supplemented with at least, six carbon sources. The carbon sources mannitol (control) and sucrose were metabilized by all isolates evaluated. The profile of intrinsic resistance to antibiotics showed that the isolates were mostly resistant to streptomycin and ampicillin, but susceptible to kanamycin and chloranphenicol. High amylolytic activity of, at least, four isolates was also demonstrated, especially for isolated 47.3b, which showed the highest enzymatic index. These results indicate the metabolic versatility of the pigeonpea rhizobia, and indicates the isolate 47.3b to further studies regarding the amylase production and characterization. PMID:24031992

  19. An Estimate of the North Atlantic Basin Tropical Cyclone Activity for the 2011 Hurricane Season

    NASA Technical Reports Server (NTRS)

    Wilson, Robert M.

    2011-01-01

    Estimates are presented for the expected level of tropical cyclone activity for the 2011 North Atlantic Basin hurricane season. It is anticipated that the frequency of tropical cyclones for the North Atlantic Basin during the 2011 hurricane season will be near to above the post-1995 means. Based on the Poisson distribution of tropical cyclone frequencies for the current more active interval 1995-2010, one computes P(r) = 63.7% for the expected frequency of the number of tropical cyclones during the 2011 hurricane season to be 14 plus or minus 3; P(r) = 62.4% for the expected frequency of the number of hurricanes to be 8 plus or minus 2; P(r) = 79.3% for the expected frequency of the number of major hurricanes to be 3 plus or minus 2; and P(r) = 72.5% for the expected frequency of the number of strikes by a hurricane along the coastline of the United States to be 1 plus or minus 1. Because El Nino is not expected to recur during the 2011 hurricane season, clearly, the possibility exists that these seasonal frequencies could easily be exceeded. Also examined are the effects of the El Nino-Southern Oscillation phase and climatic change (global warming) on tropical cyclone seasonal frequencies, the variation of the seasonal centroid (latitude and longitude) location of tropical cyclone onsets, and the variation of the seasonal peak wind speed and lowest pressure for tropical cyclones.

  20. Environmental DNA (eDNA) Detection Probability Is Influenced by Seasonal Activity of Organisms

    PubMed Central

    de Souza, Lesley S.; Godwin, James C.; Renshaw, Mark A.; Larson, Eric

    2016-01-01

    Environmental DNA (eDNA) holds great promise for conservation applications like the monitoring of invasive or imperiled species, yet this emerging technique requires ongoing testing in order to determine the contexts over which it is effective. For example, little research to date has evaluated how seasonality of organism behavior or activity may influence detection probability of eDNA. We applied eDNA to survey for two highly imperiled species endemic to the upper Black Warrior River basin in Alabama, US: the Black Warrior Waterdog (Necturus alabamensis) and the Flattened Musk Turtle (Sternotherus depressus). Importantly, these species have contrasting patterns of seasonal activity, with N. alabamensis more active in the cool season (October-April) and S. depressus more active in the warm season (May-September). We surveyed sites historically occupied by these species across cool and warm seasons over two years with replicated eDNA water samples, which were analyzed in the laboratory using species-specific quantitative PCR (qPCR) assays. We then used occupancy estimation with detection probability modeling to evaluate both the effects of landscape attributes on organism presence and season of sampling on detection probability of eDNA. Importantly, we found that season strongly affected eDNA detection probability for both species, with N. alabamensis having higher eDNA detection probabilities during the cool season and S. depressus have higher eDNA detection probabilities during the warm season. These results illustrate the influence of organismal behavior or activity on eDNA detection in the environment and identify an important role for basic natural history in designing eDNA monitoring programs. PMID:27776150

  1. [Seasonal dynamics of soil active carbon pool in a purple paddy soil in southwest China].

    PubMed

    Wu, Yan; Jiang, Chang-sheng; Hao, Qing-ju

    2012-08-01

    The seasonal dynamics of soil organic carbon (SOC), readily oxidized carbon (ROC), dissolved organic carbon (DOC) and microbial biomass carbon (MBC) in a purple paddy soil were studied in a long-term field experimental station in Chongqing, China. The results showed that the seasonal variations of the contents of SOC, ROC and MBC had similar trends in the rape growing season. The contents were much higher in the early and late stages than in the middle stage of the rape growth. SOC, ROC and MBC all achieved the highest values of 16.20 g x kg(-1), 3.58 g x kg(-1) and 309.70 mg x kg(-1) at the end of the growing period, respectively. The seasonal change of DOC content presented as a single peak and reached to the highest value of 37.64 mg x kg(-1) at the middle stage of the rape growth. The temporal dynamics of the allocation ratios of ROC, MBC and DOC were similar to that of their contents. The allocation ratios of ROC, MBC and DOC were 15.49%-23.93%, 1.44%-2.06% and 0.11%-0.32% during the rape growing season, respectively. The influencing factors of SOC and ROC contents were the soil temperature at 5 cm soil depth, soil total nitrogen content and pH. MBC content was jointly impacted by the soil temperature at 5 cm soil depth, root biomass and its C and N contents. DOC content was mainly affected by soil moisture. PMID:23213908

  2. Sexually active males prevent the display of seasonal anestrus in female goats.

    PubMed

    Delgadillo, J A; Flores, J A; Hernández, H; Poindron, P; Keller, M; Fitz-Rodríguez, G; Duarte, G; Vielma, J; Fernández, I G; Chemineau, P

    2015-03-01

    A well-defined season of sexual rest controlled by photoperiod is observed in female sheep and goats during spring and summer, delineating their "anestrous season"; bucks also decrease sexual activity at about the same time. Nutrition and/or socio-sexual stimuli play only secondary roles. However, the presence of sexually active males can reduce the length of seasonal anestrus. Whether it can also completely suppress anestrus has not been investigated. Here we tested this in goats in 3 experiments, using bucks rendered sexually active out of season by exposure to long days. The continuous presence of these males prevented goats to display seasonal anestrus: 12/14 females cycled the year round, vs. 0/13 and 0/11 for females with un-treated bucks or without bucks (experiment 1). When active bucks were removed, females immediately entered anestrus (7/7 stopped ovulating vs. 1/7 if maintained with active bucks; experiment 2). Finally, 7/7 anestrous does with bucks in sexual rest since 1.5months commenced cycling rapidly during mid-anestrous, when these bucks became sexually active following a treatment with artificial long days, vs. 0/7 with un-treated bucks or no bucks (experiment 3). The presence/withdrawal of active bucks had a highly significant effect in the three experiments (P≤0.002). Therefore, the presence of a mating opportunity can completely override the photoperiodic inhibition of reproduction of females throughout the anestrous season. Results suggest that we must re-evaluate the relative contributions of photoperiod vs. other external cues in controlling seasonal reproduction, thus offering new non-pharmaceutical ways for controlling out-of-season reproduction in small ruminants.

  3. Sphagnum-dwelling testate amoebae in subarctic bogs are more sensitive to soil warming in the growing season than in winter: the results of eight-year field climate manipulations.

    PubMed

    Tsyganov, Andrey N; Aerts, Rien; Nijs, Ivan; Cornelissen, Johannes H C; Beyens, Louis

    2012-05-01

    Sphagnum-dwelling testate amoebae are widely used in paleoclimate reconstructions as a proxy for climate-induced changes in bogs. However, the sensitivity of proxies to seasonal climate components is an important issue when interpreting proxy records. Here, we studied the effects of summer warming, winter snow addition solely and winter snow addition together with spring warming on testate amoeba assemblages after eight years of experimental field climate manipulations. All manipulations were accomplished using open top chambers in a dry blanket bog located in the sub-Arctic (Abisko, Sweden). We estimated sensitivity of abundance, diversity and assemblage structure of living and empty shell assemblages of testate amoebae in the living and decaying layers of Sphagnum. Our results show that, in a sub-arctic climate, testate amoebae are more sensitive to climate changes in the growing season than in winter. Summer warming reduced species richness and shifted assemblage composition towards predominance of xerophilous species for the living and empty shell assemblages in both layers. The higher soil temperatures during the growing season also decreased abundance of empty shells in both layers hinting at a possible increase in their decomposition rates. Thus, although possible effects of climate changes on preservation of empty shells should always be taken into account, species diversity and structure of testate amoeba assemblages in dry subarctic bogs are sensitive proxies for climatic changes during the growing season.

  4. Sphagnum-dwelling testate amoebae in subarctic bogs are more sensitive to soil warming in the growing season than in winter: the results of eight-year field climate manipulations.

    PubMed

    Tsyganov, Andrey N; Aerts, Rien; Nijs, Ivan; Cornelissen, Johannes H C; Beyens, Louis

    2012-05-01

    Sphagnum-dwelling testate amoebae are widely used in paleoclimate reconstructions as a proxy for climate-induced changes in bogs. However, the sensitivity of proxies to seasonal climate components is an important issue when interpreting proxy records. Here, we studied the effects of summer warming, winter snow addition solely and winter snow addition together with spring warming on testate amoeba assemblages after eight years of experimental field climate manipulations. All manipulations were accomplished using open top chambers in a dry blanket bog located in the sub-Arctic (Abisko, Sweden). We estimated sensitivity of abundance, diversity and assemblage structure of living and empty shell assemblages of testate amoebae in the living and decaying layers of Sphagnum. Our results show that, in a sub-arctic climate, testate amoebae are more sensitive to climate changes in the growing season than in winter. Summer warming reduced species richness and shifted assemblage composition towards predominance of xerophilous species for the living and empty shell assemblages in both layers. The higher soil temperatures during the growing season also decreased abundance of empty shells in both layers hinting at a possible increase in their decomposition rates. Thus, although possible effects of climate changes on preservation of empty shells should always be taken into account, species diversity and structure of testate amoeba assemblages in dry subarctic bogs are sensitive proxies for climatic changes during the growing season. PMID:21839679

  5. Perilipin+ embryonic preadipocytes actively proliferate along growing vasculatures for adipose expansion.

    PubMed

    Hong, Ki Yong; Bae, Hosung; Park, Intae; Park, Dae-Young; Kim, Kyun Hoo; Kubota, Yoshiaki; Cho, Eui-Sic; Kim, Hail; Adams, Ralf H; Yoo, Ook-Joon; Koh, Gou Young

    2015-08-01

    Despite the growing interest in adipose tissue as a therapeutic target of metabolic diseases, the identity of adipocyte precursor cells (preadipocytes) and the formation of adipose tissue during embryonic development are still poorly understood. Here, we clarified the identity and dynamic processes of preadipocytes in mouse white adipose tissue during embryogenesis through direct examination, lineage tracing and culture systems. Surprisingly, we found that lipid-lacking but perilipin(+) or adiponectin(+) proliferating preadipocytes started to emerge at embryonic day 16.5, and these cells underwent active proliferation until birth. Moreover, these preadipocytes resided as clusters and were distributed along growing adipose vasculatures. Importantly, the embryonic preadipocytes exhibited considerable coexpression of stem cell markers, such as CD24, CD29 and PDGFRα, and a small portion of preadipocytes were derived from PDGFRβ(+) mural cells, in contrast to the adult preadipocytes present in the stromal vascular fraction. Further analyses with in vitro and ex vivo culture systems revealed a stepwise but dynamic regulation of preadipocyte formation and differentiation during prenatal adipogenesis. To conclude, we unraveled the identity and characteristics of embryonic preadipocytes, which are crucial for the formation and expansion of adipose tissue during embryogenesis.

  6. Seasonality of fertility measured by physical activity traits in Holstein cows.

    PubMed

    Ismael, Ahmed; Strandberg, Erling; Berglund, Britt; Fogh, Anders; Løvendahl, Peter

    2016-04-01

    Seasonality of female fertility traits, including the interval from calving to first high activity (CFHA), duration of high activity episode (DHA), and strength of high activity episode (SHA) of first estrus, were studied. The physical activity traits were derived from electronic activity tags for 20,794 Holstein cows in 135 commercial Holstein herds in Denmark. Data were categorized in 3 ways: (1) into 4 seasons of calving: winter (January-March), spring (April-June), summer (July-September), and fall (October-December); (2) into 2 seasons: a cold season (October-March) and a warm season (April-September); and (3) into an increasing light season (IL; January-June), where daylight hours gradually increased, and a decreasing light season (DL; July-December), where daylight hours gradually decreased. At the phenotypic level, least squares means of CFHA were highest at 55d for cows calving in December and lowest at 31d for cows calving in September. The highest least squares means of DHA and SHA were recorded for cows calving in November and lowest for cows calving in May and June. Genetic parameters for all traits were estimated using average information-REML in a bivariate animal model that treated the same trait in different calving seasons as different traits. Heritability estimates for CFHA were highest for the winter season (0.13) and low for the other seasons (0.03-0.04), whereas heritability estimates for DHA and SHA were lowest for winter and highest for fall. Heritability estimates for CFHA for the cold season (0.17) was higher than that for the warm season (0.10). Heritability estimates of CFHA for the IL season (0.12) was higher than for the DL season (0.07), but the opposite pattern was found for DHA and SHA. Genetic correlations (rA) of CFHA between winter and summer (rA=0.34 ± 0.27), and winter and fall (rA=0.65 ± 0.20) were significantly lower than unity. The corresponding correlations of DHA and SHA between seasons were all close to unity, except

  7. Genetic diversity and insecticide resistance during the growing season in the green peach aphid (Hemiptera: Aphididae) on primary and secondary hosts: a farm-scale study in Central Chile.

    PubMed

    Rubiano-Rodríguez, J A; Fuentes-Contreras, E; Figueroa, C C; Margaritopoulos, J T; Briones, L M; Ramírez, C C

    2014-04-01

    The seasonal dynamics of neutral genetic diversity and the insecticide resistance mechanisms of insect pests at the farm scale are still poorly documented. Here this was addressed in the green peach aphid Myzus persicae (Sulzer) (Hemiptera: Aphididae) in Central Chile. Samples were collected from an insecticide sprayed peach (Prunus persica L.) orchard (primary host), and a sweet-pepper (Capsicum annum var. grossum L.) field (secondary host). In addition, aphids from weeds (secondary hosts) growing among these crops were also sampled. Many unique multilocus genotypes were found on peach trees, while secondary hosts were colonized mostly by the six most common genotypes, which were predominantly sensitive to insecticides. In both fields, a small but significant genetic differentiation was found between aphids on the crops vs. their weeds. Within-season comparisons showed genetic differentiation between early and late season samples from peach, as well as for weeds in the peach orchard. The knock-down resistance (kdr) mutation was detected mostly in the heterozygote state, often associated with modified acetylcholinesterase throughout the season for both crops. This mutation was found in high frequency, mainly in the peach orchard. The super-kdr mutation was found in very low frequencies in both crops. This study provides farm-scale evidence that the aphid M. persicae can be composed of slightly different genetic groups between contiguous populations of primary and secondary hosts exhibiting different dynamics of insecticide resistance through the growing season. PMID:24484894

  8. Genetic diversity and insecticide resistance during the growing season in the green peach aphid (Hemiptera: Aphididae) on primary and secondary hosts: a farm-scale study in Central Chile.

    PubMed

    Rubiano-Rodríguez, J A; Fuentes-Contreras, E; Figueroa, C C; Margaritopoulos, J T; Briones, L M; Ramírez, C C

    2014-04-01

    The seasonal dynamics of neutral genetic diversity and the insecticide resistance mechanisms of insect pests at the farm scale are still poorly documented. Here this was addressed in the green peach aphid Myzus persicae (Sulzer) (Hemiptera: Aphididae) in Central Chile. Samples were collected from an insecticide sprayed peach (Prunus persica L.) orchard (primary host), and a sweet-pepper (Capsicum annum var. grossum L.) field (secondary host). In addition, aphids from weeds (secondary hosts) growing among these crops were also sampled. Many unique multilocus genotypes were found on peach trees, while secondary hosts were colonized mostly by the six most common genotypes, which were predominantly sensitive to insecticides. In both fields, a small but significant genetic differentiation was found between aphids on the crops vs. their weeds. Within-season comparisons showed genetic differentiation between early and late season samples from peach, as well as for weeds in the peach orchard. The knock-down resistance (kdr) mutation was detected mostly in the heterozygote state, often associated with modified acetylcholinesterase throughout the season for both crops. This mutation was found in high frequency, mainly in the peach orchard. The super-kdr mutation was found in very low frequencies in both crops. This study provides farm-scale evidence that the aphid M. persicae can be composed of slightly different genetic groups between contiguous populations of primary and secondary hosts exhibiting different dynamics of insecticide resistance through the growing season.

  9. Language through the Seasons: Dramatic Play Activities for Early Childhood Learners.

    ERIC Educational Resources Information Center

    Amdur, Judith

    This workbook brings together activities to aid in motivating children to concentrate, listen, respond, think, and learn. The activities rely upon play-like tasks involving drama, music, and other forms of creative expression. The activities are organized by the season in which they are appropriate and include songs, dramatic sequences, stories,…

  10. Antileishmanial activity of some plants growing in Algeria: Juglans regia, Lawsonia inermis and Salvia officinalis.

    PubMed

    Serakta, M; Djerrou, Z; Mansour-Djaalab, H; Kahlouche-Riachi, F; Hamimed, S; Trifa, W; Belkhiri, A; Edikra, N; Hamdi Pacha, Y

    2013-01-01

    The current study was undertaken to evaluate in vitro the antileishmanial activity of three plants growing wild in Algeria : Juglans regia, Lawsonia inermis and Salvia officinalis. The hydroalcoholic extracts of these plants were tested on the growth of the promastigotes of Leishmania major. The plant extract effects were compared with three controls : CRL1 composed of 1 ml RPMI inoculated with 10(6) of promastigotes, CRL2 composed of 1 ml RPMI inoculated with 10(6) of promastigotes and 100 µl of hydroalcoholic solvent, CRL3 composed of 1 ml RPMI inoculated with 10(6) of promastigotes and 100 µl of Glucantim as a reference drug in the management of leishmaniasis. The results showed that both J. regia and L. inermis extracts reduced the promastigotes number significantly (P<0.01). however, S. officinalis showed a total inhibition of the Leishmania major growth.

  11. The persistence of equatorial spread F - an analysis on seasonal, solar activity and geomagnetic activity aspects

    NASA Astrophysics Data System (ADS)

    Sreeja, V.; Devasia, C. V.; Ravindran, Sudha; Sridharan, R.

    2009-02-01

    The persistence (duration) of Equatorial Spread F (ESF), which has significant impact on communication systems, is addressed. Its behavior during different seasons and geomagnetic activity levels under the solar maximum (2001) and minimum (2006) conditions, is reported using the data from the magnetic equatorial location of Trivandrum (8.5° N; 77° E; dip 0.5° N) in India. The study reveals that the persistence of the irregularities can be estimated to a reasonable extent by knowing the post sunset F region vertical drift velocity (Vz) and the magnetic activity index Kp. Any sort of advance information on the possible persistence of the ionospheric irregularities responsible for ESF is important for understanding the scintillation morphology, and the results which form the first step in this direction are presented and discussed.

  12. Creating leptin-like biofunctions by active immunization against chicken leptin receptor in growing chickens.

    PubMed

    Lei, M M; Wu, S Q; Shao, X B; Li, X W; Chen, Z; Ying, S J; Shi, Z D

    2015-01-01

    In this study, immunization against chicken leptin receptor (cLEPR) extracellular domain (ECD) was applied to investigate leptin regulation and LEPR biofunction in growing chicken pullets. A recombinant protein (cLEPR ECD) based on the cLEPR complemenary DNA sequence corresponding to the 582nd to 796th amino acid residues of cLEPR mature peptide was prepared and used as antigen. Immunization against cLEPR ECD in growing chickens increased anti-cLEPR ECD antibody titers in blood, enhanced proportions of phosphorylated janus kinase 2 (JAK2) and served as signal transducer and activator of transcription 3 (STAT3) protein in liver tissue. Chicken live weight gain and abdominal fat mass were significantly decreased (P < 0.05), but feed intake was stimulated by cLEPR ECD immunization (P < 0.05). The treatment also upregulated the gene expression levels of lepR, AMP-activated protein kinase (AMPK), acetyl CoA carboxylase-2 (ACC2), and uncoupling protein 3 (UCP3) in liver, abdominal fat, and breast muscle (P < 0.05) but decreased fasn expression levels (P < 0.01). Apart from that of lepR, the expression of appetite-regulating genes, such as orexigenic genes, agouti-related peptide (AgRP) and neuropeptide Y (NPY), were upregulated (P < 0.01), whereas the anorexigenic gene proopiomelanocortin (POMC) was downregulated in the hypothalamic tissue of cLEPR-immunized pullets (P < 0.01). Blood concentrations of metabolic molecules, such as glucose, triglycerides, and very-low-density lipoprotein, were significantly decreased in cLEPR-immunized pullets but those of cholesterol, high-density lipoprotein, and low-density lipoprotein increased. These results demonstrate that antibodies to membrane proximal cLEPR ECD enhance cLEPR signal transduction, which stimulates metabolism and reduces fat deposition in chickens.

  13. Comparative study of volatile oil content and antimicrobial activity of pecan cultivars growing in Egypt.

    PubMed

    El Hawary, Seham S; Zaghloul, Soumaya S; El Halawany, Ali M; El Bishbishy, Mahitab H

    2013-11-01

    The volatile oils obtained from the leaves of four pecan cultivars growing in Egypt were evaluated for their chemical composition and antimicrobial activity. The selected cultivars (cv.) were Carya illinoinensis (Wangneh.) K. Koch. cv. Wichita, C. illinoinensis cv. Western Schley, C. illinoinensis cv. Cherokee, and C. illinoinensis cv. Sioux. The gas chromatography-mass spectrometry analyses revealed that the volatile oils from samples of the different cultivars differ in composition and percentage of their components. β-Curcumene was found as the major constituent of the cv. Wichita oil, whereas germacrene D was the major component of cv. Sioux, cv. Cherokee, and cv. Western Schley. The antimicrobial activity was assayed using the Kirby-Bauer Method by measuring the zone of inhibition of growth. All volatile oils displayed an antimicrobial activity against the tested bacterial strains. On the other hand, only the volatile oil of cv. Wichita showed an antifungal effect on Aspergillus flavus. This work has identified candidates of volatile oils for future in vivo studies to develop antibiotic substitutes for the diminution of human and animal pathogenic bacteria. Nevertheless, the variations of the volatile oil components and antimicrobial potencies of the different studied cultivars, necessitate identifying the cultivars used in future studies. PMID:24180553

  14. Implications of climatic seasonality on activity patterns and resource use by sympatric peccaries in northern Pantanal.

    PubMed

    Hofmann, Gabriel Selbach; Coelho, Igor Pfeifer; Bastazini, Vinicius Augusto Galvão; Cordeiro, José Luís Passos; de Oliveira, Luiz Flamarion Barbosa

    2016-03-01

    We evaluated the effects of climate seasonality from a thermal and water availability perspective on the activity patterns and resource use of Pecari tajacu and Tayassu pecari during wet and dry seasons in the northeastern Brazilian Pantanal. We used camera traps and temperature sensors to record species activity patterns in relation to temperature, established five habitat categories based on flooding intensity and local vegetation characteristics, assessed the activity patterns of each species in dry and wet periods and in artificial water bodies using circular statistical metrics, and calculated niche amplitude and overlap on three axes (temperature, time, and habitat) in both periods. Peccaries shared a strong resemblance in resource use and in their responses to seasonal variations in the tested gradients. The activity patterns of both species exhibited a significant correlation with air temperature on all the evaluated measures, and both species strongly reduced their activity when the air temperature exceeded 35 °C. High temperatures associated with low water availability were most likely responsible for the changes in species activity patterns, which resulted in an increased temporal overlap in habitat use throughout the dry season. However, the peccaries avoided intensively flooded habitats; therefore, the habitat gradient overlap was greater during the wet period. Our results show that an increase in niche overlap on the environmental gradient as a result of climatic seasonality may be partially compensated by a reduction in other niche dimensions. In this case, temporal partitioning appears to be an important, viable mechanism to reduce competition by potentially competing species.

  15. Implications of climatic seasonality on activity patterns and resource use by sympatric peccaries in northern Pantanal

    NASA Astrophysics Data System (ADS)

    Hofmann, Gabriel Selbach; Coelho, Igor Pfeifer; Bastazini, Vinicius Augusto Galvão; Cordeiro, José Luís Passos; de Oliveira, Luiz Flamarion Barbosa

    2016-03-01

    We evaluated the effects of climate seasonality from a thermal and water availability perspective on the activity patterns and resource use of Pecari tajacu and Tayassu pecari during wet and dry seasons in the northeastern Brazilian Pantanal. We used camera traps and temperature sensors to record species activity patterns in relation to temperature, established five habitat categories based on flooding intensity and local vegetation characteristics, assessed the activity patterns of each species in dry and wet periods and in artificial water bodies using circular statistical metrics, and calculated niche amplitude and overlap on three axes (temperature, time, and habitat) in both periods. Peccaries shared a strong resemblance in resource use and in their responses to seasonal variations in the tested gradients. The activity patterns of both species exhibited a significant correlation with air temperature on all the evaluated measures, and both species strongly reduced their activity when the air temperature exceeded 35 °C. High temperatures associated with low water availability were most likely responsible for the changes in species activity patterns, which resulted in an increased temporal overlap in habitat use throughout the dry season. However, the peccaries avoided intensively flooded habitats; therefore, the habitat gradient overlap was greater during the wet period. Our results show that an increase in niche overlap on the environmental gradient as a result of climatic seasonality may be partially compensated by a reduction in other niche dimensions. In this case, temporal partitioning appears to be an important, viable mechanism to reduce competition by potentially competing species.

  16. Seasonal Drivers of Pneumococcal Disease Incidence: Impact of Bacterial Carriage and Viral Activity

    PubMed Central

    Weinberger, Daniel M.; Grant, Lindsay R.; Steiner, Claudia A.; Weatherholtz, Robert; Santosham, Mathuram; Viboud, Cécile; O'Brien, Katherine L.

    2014-01-01

    Background. Winter-seasonal epidemics of pneumococcal disease provide an opportunity to understand the drivers of incidence. We sought to determine whether seasonality of invasive pneumococcal disease is caused by increased nasopharyngeal transmission of the bacteria or increased susceptibility to invasive infections driven by cocirculating winter respiratory viruses. Methods. We analyzed pneumococcal carriage and invasive disease data collected from children <7 years old in the Navajo/White Mountain Apache populations between 1996 and 2012. Regression models were used to quantify seasonal variations in carriage prevalence, carriage density, and disease incidence. We also fit a multivariate model to determine the contribution of carriage prevalence and RSV activity to pneumococcal disease incidence while controlling for shared seasonal factors. Results. The seasonal patterns of invasive pneumococcal disease epidemics varied significantly by clinical presentation: bacteremic pneumococcal pneumonia incidence peaked in late winter, whereas invasive nonpneumonia pneumococcal incidence peaked in autumn. Pneumococcal carriage prevalence and density also varied seasonally, with peak prevalence occurring in late autumn. In a multivariate model, RSV activity was associated with significant increases in bacteremic pneumonia cases (attributable percentage, 15.5%; 95% confidence interval [CI], 1.8%–26.1%) but was not associated with invasive nonpneumonia infections (8.0%; 95% CI, −4.8% to 19.3%). In contrast, seasonal variations in carriage prevalence were associated with significant increases in invasive nonpneumonia infections (31.4%; 95% CI, 8.8%–51.4%) but not with bacteremic pneumonia. Conclusions.The seasonality of invasive pneumococcal pneumonia could be due to increased susceptibility to invasive infection triggered by viral pathogens, whereas seasonality of other invasive pneumococcal infections might be primarily driven by increased nasopharyngeal

  17. Antioxidant and antibacterial activities of extracts from Conyza bonariensis growing in Yemen.

    PubMed

    Thabit, Riyadh Abdulmajid Saleh; Cheng, Xiang-Rong; Tang, Xue; Sun, Jin; Shi, Yong-Hui; Le, Guo-Wei

    2015-01-01

    This study aims to examine the antioxidant and antibacterial activities and phenolic contents of Conyza bonariensis growing in Yemen. The whole plants of C. bonariensis were ultrasonically extracted by ethanol. The antioxidant activity of the extract was determined by 2,2-diphenyl-1-picrylhydrazyl (DPPH) and β-carotene bleaching (BCB). The effectiveness of the extract on the growth inhibition of some indicators of foodborne illness bacteria were investigated by agar well diffusion assay. The total phenols (TP), total flavonoids (TF), total tannins (TT), and total anthocyanins (TA) were determined by Folin-Ciocalteu method, aluminium chloride method, Folin and Ciocalteu method, and pH-differential method, respectively. The extract of C. bonariensis possessed TP 144.1 mg/g, TF 143 mg/g, TT 0.99mg/g, and TA 0.97mg 100g, with 94.57% inhibition of DPPH and 92.47% inhibition of BCB, and strong inhibitory effects against tested bacteria, which was approximate to those of peel extract of Punica granatum.

  18. Antioxidant and antibacterial activities of extracts from Conyza bonariensis growing in Yemen.

    PubMed

    Thabit, Riyadh Abdulmajid Saleh; Cheng, Xiang-Rong; Tang, Xue; Sun, Jin; Shi, Yong-Hui; Le, Guo-Wei

    2015-01-01

    This study aims to examine the antioxidant and antibacterial activities and phenolic contents of Conyza bonariensis growing in Yemen. The whole plants of C. bonariensis were ultrasonically extracted by ethanol. The antioxidant activity of the extract was determined by 2,2-diphenyl-1-picrylhydrazyl (DPPH) and β-carotene bleaching (BCB). The effectiveness of the extract on the growth inhibition of some indicators of foodborne illness bacteria were investigated by agar well diffusion assay. The total phenols (TP), total flavonoids (TF), total tannins (TT), and total anthocyanins (TA) were determined by Folin-Ciocalteu method, aluminium chloride method, Folin and Ciocalteu method, and pH-differential method, respectively. The extract of C. bonariensis possessed TP 144.1 mg/g, TF 143 mg/g, TT 0.99mg/g, and TA 0.97mg 100g, with 94.57% inhibition of DPPH and 92.47% inhibition of BCB, and strong inhibitory effects against tested bacteria, which was approximate to those of peel extract of Punica granatum. PMID:25553691

  19. Seasonal Variations in Notification of Active Tuberculosis Cases in China, 2005–2012

    PubMed Central

    Li, Xin-Xu; Wang, Li-Xia; Zhang, Hui; Du, Xin; Jiang, Shi-Wen; Shen, Tao; Zhang, Yan-Ping; Zeng, Guang

    2013-01-01

    Background Although seasonal variation in tuberculosis (TB) incidence has been described in many countries, it remains unknown in China. Methods A time series decomposition analysis (X-12-ARIMA) was performed to examine the seasonal variation in active TB cases nationwide from 2005 through 2012 in China. Seasonal amplitude was calculated for the evaluation of TB seasonal variation. Results A total of 7.78 million active TB cases were reported over a period of 8 years. A spring peak (April) was observed with seasonal amplitude of 46.3%, compared with the winter trough (February). Most cases in provinces with subtropical and tropical monsoon climate showed lower amplitudes than those in temperate continental, plateau and mountain climate regions. The magnitude of seasonality varied inversely with annual average temperature, r (95% CI) = -0.71 (-0.79, -0.61). The seasonal amplitudes were 56.7, 60.5, 40.6, 46.4 and 50.9% for patients aged ≤14, 15–24, 25–44, 45–64, and ≥65 years, respectively. Students demonstrated greater seasonal amplitude than peasants, migrant workers and workers (115.3% vs. 43.5, 41.6 and 48.1%). Patients with pulmonary TB had lower amplitude compared to patients with pleural and other extra-pulmonary TB (EPTB) (45.9% vs. 52.0 and 56.3%). Relapse cases with sputum smear positive TB (SS+ TB) had significantly higher seasonal amplitude compared to new cases with sputum smear positive TB (52.2% vs. 41.6%). Conclusions TB is a seasonal disease in China. The peak and trough of TB transmission actually are in winter and in autumn respectively after factors of delay are removed. Higher amplitudes of TB seasonality are more likely to happen in temperate continental, plateau and mountain climate regions and regions with lower annual average temperature, and young person, students, patients with EPTB and relapse cases with SS+ TB are more likely to be affected by TB seasonality. PMID:23874512

  20. Using an active sensor to make in-season nitrogen recommendations for corn

    Technology Transfer Automated Retrieval System (TEKTRAN)

    An active crop canopy reflectance sensor could increase N-use efficiency in corn (Zea mays L.), if temporal and spatial variability in soil N availability and plant demand are adequately accounted for with an in-season application. Our objective was to evaluate the success of using an active sensor ...

  1. Seasonal forecasting of lightning and thunderstorm activity in tropical and temperate regions of the world.

    PubMed

    Dowdy, Andrew J

    2016-01-01

    Thunderstorms are convective systems characterised by the occurrence of lightning. Lightning and thunderstorm activity has been increasingly studied in recent years in relation to the El Niño/Southern Oscillation (ENSO) and various other large-scale modes of atmospheric and oceanic variability. Large-scale modes of variability can sometimes be predictable several months in advance, suggesting potential for seasonal forecasting of lightning and thunderstorm activity in various regions throughout the world. To investigate this possibility, seasonal lightning activity in the world's tropical and temperate regions is examined here in relation to numerous different large-scale modes of variability. Of the seven modes of variability examined, ENSO has the strongest relationship with lightning activity during each individual season, with relatively little relationship for the other modes of variability. A measure of ENSO variability (the NINO3.4 index) is significantly correlated to local lightning activity at 53% of locations for one or more seasons throughout the year. Variations in atmospheric parameters commonly associated with thunderstorm activity are found to provide a plausible physical explanation for the variations in lightning activity associated with ENSO. It is demonstrated that there is potential for accurately predicting lightning and thunderstorm activity several months in advance in various regions throughout the world. PMID:26865431

  2. Seasonal forecasting of lightning and thunderstorm activity in tropical and temperate regions of the world

    PubMed Central

    Dowdy, Andrew J.

    2016-01-01

    Thunderstorms are convective systems characterised by the occurrence of lightning. Lightning and thunderstorm activity has been increasingly studied in recent years in relation to the El Niño/Southern Oscillation (ENSO) and various other large-scale modes of atmospheric and oceanic variability. Large-scale modes of variability can sometimes be predictable several months in advance, suggesting potential for seasonal forecasting of lightning and thunderstorm activity in various regions throughout the world. To investigate this possibility, seasonal lightning activity in the world’s tropical and temperate regions is examined here in relation to numerous different large-scale modes of variability. Of the seven modes of variability examined, ENSO has the strongest relationship with lightning activity during each individual season, with relatively little relationship for the other modes of variability. A measure of ENSO variability (the NINO3.4 index) is significantly correlated to local lightning activity at 53% of locations for one or more seasons throughout the year. Variations in atmospheric parameters commonly associated with thunderstorm activity are found to provide a plausible physical explanation for the variations in lightning activity associated with ENSO. It is demonstrated that there is potential for accurately predicting lightning and thunderstorm activity several months in advance in various regions throughout the world. PMID:26865431

  3. Seasonal forecasting of lightning and thunderstorm activity in tropical and temperate regions of the world.

    PubMed

    Dowdy, Andrew J

    2016-02-11

    Thunderstorms are convective systems characterised by the occurrence of lightning. Lightning and thunderstorm activity has been increasingly studied in recent years in relation to the El Niño/Southern Oscillation (ENSO) and various other large-scale modes of atmospheric and oceanic variability. Large-scale modes of variability can sometimes be predictable several months in advance, suggesting potential for seasonal forecasting of lightning and thunderstorm activity in various regions throughout the world. To investigate this possibility, seasonal lightning activity in the world's tropical and temperate regions is examined here in relation to numerous different large-scale modes of variability. Of the seven modes of variability examined, ENSO has the strongest relationship with lightning activity during each individual season, with relatively little relationship for the other modes of variability. A measure of ENSO variability (the NINO3.4 index) is significantly correlated to local lightning activity at 53% of locations for one or more seasons throughout the year. Variations in atmospheric parameters commonly associated with thunderstorm activity are found to provide a plausible physical explanation for the variations in lightning activity associated with ENSO. It is demonstrated that there is potential for accurately predicting lightning and thunderstorm activity several months in advance in various regions throughout the world.

  4. The activity of recent anti-allergic drugs in the treatment of seasonal allergic rhinitis.

    PubMed

    Wang, D; Clement, P; Smitz, J; De Waele, M

    1996-01-01

    Two experiments were performed during the pollen season to study the activity of different antiallergic drugs in the treatment of seasonal allergic rhinitis. Nasal allergen challenge (NAC) was performed to mimic an acute attack of allergic rhinitis and to objectively evaluate the effect of the drugs on the early-phase reaction during the season. The first study assessed the effect of H1 (Cetirizine 10 mg a day) and of a combination of H1 (Cetirizine 10 mg) plus H2 (Cimetidine 800 mg a day) antagonists on nasal symptoms, mediator release and eosinophil count in a group of 16 patients with seasonal allergic rhinitis. During the same season a second study compared in a randomized way (2 parallel groups) the effect of Budesonide (Rhinocort Aqua) and Azelastine (Allergodil nasal spray) in a group of 14 patients. Results showed that both antihistamines, applied topically of dosed orally, reduced sneezing even when significant increases of histamine concentration in nasal secretions were evidenced immediately after NAC. When a combination of Cetirizine and Cimetidine was administered, a significant (p < 0.01) reduction of nasal airway resistance and increase of nasal airflow after NAC were demonstrated as well. In addition, topical application of Budesonide showed a strong (p < 0.01) effect on the infiltration and activation of eosinophils during the season, and on tryptase release after NAC. These effects lasted at least for one week after therapy. PMID:8669268

  5. The activity of recent anti-allergic drugs in the treatment of seasonal allergic rhinitis.

    PubMed

    Wang, D; Clement, P; Smitz, J; De Waele, M

    1996-01-01

    Two experiments were performed during the pollen season to study the activity of different antiallergic drugs in the treatment of seasonal allergic rhinitis. Nasal allergen challenge (NAC) was performed to mimic an acute attack of allergic rhinitis and to objectively evaluate the effect of the drugs on the early-phase reaction during the season. The first study assessed the effect of H1 (Cetirizine 10 mg a day) and of a combination of H1 (Cetirizine 10 mg) plus H2 (Cimetidine 800 mg a day) antagonists on nasal symptoms, mediator release and eosinophil count in a group of 16 patients with seasonal allergic rhinitis. During the same season a second study compared in a randomized way (2 parallel groups) the effect of Budesonide (Rhinocort Aqua) and Azelastine (Allergodil nasal spray) in a group of 14 patients. Results showed that both antihistamines, applied topically of dosed orally, reduced sneezing even when significant increases of histamine concentration in nasal secretions were evidenced immediately after NAC. When a combination of Cetirizine and Cimetidine was administered, a significant (p < 0.01) reduction of nasal airway resistance and increase of nasal airflow after NAC were demonstrated as well. In addition, topical application of Budesonide showed a strong (p < 0.01) effect on the infiltration and activation of eosinophils during the season, and on tryptase release after NAC. These effects lasted at least for one week after therapy.

  6. Dust loading in Gusev crater, Mars: Results from two active dust devil seasons

    NASA Astrophysics Data System (ADS)

    Waller, D. A.; Greeley, R.; Neakrase, L. D.; Landis, G. A.; Whelley, P.; Thompson, S. D.

    2009-12-01

    Dust devils dominate the volcanic plains at the Mars Exploration Rover (MER) landing site within the Low Albedo Zone (LAZ) in Gusev Crater. Previous studies indicate that the inferred pressure drop within the dust devil core allows the vortex to lift large amounts of unconsolidated dust high into the atmosphere which contributes to the atmospheric haze. Previous laboratory results indicate that dust devils are efficient in lifting very fine-grained (<10 μm) material, even when boundary layer winds do not exceed previously predicted threshold wind speeds (~30-35 m/s at 1.5 m above the surface for Mars conditions). Since landing in Gusev crater in January 2004, MER Spirit has obtained data for two dust devil seasons (defined as the period of time when the first and last dust devils were imaged), with a third season currently being analyzed. These seasons typically correspond to southern spring and summer, when winds capable of lifting sediment are determined to be most frequent. All observations for Season One were taken as Spirit neared the summit of Husband Hill. During Season Two Spirit imaged dust devils in the plains as it traversed within the Inner Basin, a low-lying area in the Columbia Hills complex. All results were extrapolated so that they are representative of the entire LAZ. Season One lasted 270 sols (March 2005 to December 2005 corresponding to Ls 173.2 to 339.5 degrees), whereas Season Two lasted 153 sols (January 2007 to June 2007 corresponding to Ls 171.2 to 266.7 degrees) and ended suddenly on sol 1240 just after the dust devil frequency peaked for the season. This abrupt drop in dust devil activity corresponded to atmospheric opacity levels that exceeded 1.0 and the onset of a global dust storm that originated in the southern hemisphere that engulfed Gusev within weeks. Results show a large contrast in activity between the two seasons. An 81% decrease in dust devil frequency across the plains was found in Season Two. 533 dust devils were imaged

  7. Mercuric reductase activity and evidence of broad-spectrum mercury resistance among clinical isolates of rapidly growing mycobacteria

    SciTech Connect

    Steingrube, V.A.; Wallace, R.J. Jr.; Steele, L.C.; Pang, Y.J. )

    1991-05-01

    Resistance to mercury was evaluated in 356 rapidly growing mycobacteria belonging to eight taxonomic groups. Resistance to inorganic Hg2+ ranged from 0% among the unnamed third biovariant complex of Mycobacterium fortuitum to 83% among M. chelonae-like organisms. With cell extracts and 203Hg(NO3)2 as the substrate, mercuric reductase (HgRe) activity was demonstrable in six of eight taxonomic groups. HgRe activity was inducible and required NADPH or NADH and a thiol donor for optimai activity. Species with HgRe activity were also resistant to organomercurial compounds, including phenylmercuric acetate. Attempts at intraspecies and intragenus transfer of HgRe activity by conjugation or transformation were unsuccessful. Mercury resistance is common in rapidly growing mycobacteria and appears to function via the same inducible enzyme systems already defined in other bacterial species. This system offers potential as a strain marker for epidemiologic investigations and for studying genetic systems in rapidly growing mycobacteria.

  8. Seasonal distribution of microbial activity in bioaerosols in the outdoor environment of the Qingdao coastal region

    NASA Astrophysics Data System (ADS)

    Zhong, Xi; Qi, Jianhua; Li, Hongtao; Dong, Lijie; Gao, Dongmei

    2016-09-01

    Microbial activities in the atmosphere can indicate the physiological processes of microorganisms and can indirectly affect cloud formation and environmental health. In this study, the microbial activity in bioaerosols collected in the Qingdao coastal region was investigated using the fluorescein diacetate (FDA) hydrolysis method to detect the enzyme activity of microorganisms. The results showed that the microbial activity ranged from 5.49 to 102 ng/m3 sodium fluorescein from March 2013 to February 2014; the average value was 34.4 ng/m3. Microbial activity has no statistical correlation with total microbial quantity. Multiple linear regression analysis showed that meteorological factors such as atmospheric temperature, relative humidity and wind speed accounted for approximately 35.7% of the variation of the microbial activity, although their individual impacts on microbial activity varied. According to the correlation analysis, atmospheric temperature and wind speed had a significant positive and negative influence on microbial activity, respectively, whereas relative humidity and wind direction had no significant influence. The seasonal distribution of microbial activity in bioaerosols was in the order of summer > autumn > winter > spring, with high fluctuations in the summer and autumn. Microbial activity in bioaerosols differed in different weather conditions such as the sunny, foggy, and hazy days of different seasons. Further in situ observations in different weather conditions at different times and places are needed to understand the seasonal distribution characteristics of microbial activity in bioaerosols and the influence factors of microbial activity.

  9. Effect of gender on meat quality in lamb from extensive and intensive grazing systems when slaughtered at the end of the growing season.

    PubMed

    Lind, Vibeke; Berg, Jan; Eilertsen, Svein Morten; Hersleth, Margrethe; Eik, Lars Olav

    2011-06-01

    In Norway, most lambs are slaughtered at the end of the grazing season in September. An increased demand for fresh meat during the off-season may change this pattern. Castration of male lambs is not permitted, and off-season slaughtering may affect the acceptability of the meat. The objective of this study was to determine the effect of gender and the interaction between gender and diet on meat quality from Norwegian White Sheep lambs slaughtered in September. In two different experiments, 22 and 29 males compared with 22 and 46 female lambs, respectively, were used. Loin samples of M. Longissimus dorsi were analysed for sensory profile and fatty acid composition. Meat from male lambs in Experiment 2 had higher scores for cloying and rancid flavour, and lower scores for sour and sweet taste compared to meat from female lambs. It is concluded that even at the normal slaughtering time in September, significant differences between genders may occur.

  10. Effect of altitude and season on microbial activity, abundance and community structure in Alpine forest soils.

    PubMed

    Siles, José A; Cajthaml, Tomas; Minerbi, Stefano; Margesin, Rosa

    2016-03-01

    In the current context of climate change, the study of microbial communities along altitudinal gradients is especially useful. Only few studies considered altitude and season at the same time. We characterized four forest sites located in the Italian Alps, along an altitude gradient (545-2000 m a.s.l.), to evaluate the effect of altitude in spring and autumn on soil microbial properties. Each site in each season was characterized with regard to soil temperature, physicochemical properties, microbial activities (respiration, enzymes), community level physiological profiles (CLPP), microbial abundance and community structure (PLFA). Increased levels of soil organic matter (SOM) and nutrients were found at higher altitudes and in autumn, resulting in a significant increase of (soil dry-mass related) microbial activities and abundance at higher altitudes. Significant site- and season-specific effects were found for enzyme production. The significant interaction of the factors site and incubation temperature for soil microbial activities indicated differences in microbial communities and their responses to temperature among sites. CLPP revealed site-specific effects. Microbial community structure was influenced by altitudinal, seasonal and/or site-specific effects. Correlations demonstrated that altitude, and not season, was the main factor determining the changes in abiotic and biotic characteristics at the sites investigated.

  11. Dealing with Climate Change and Variability in the Growing Season: a U2U Decision Support Tool for Central United States Corn Producers Based on Corn Growing Degree Days

    NASA Astrophysics Data System (ADS)

    Angel, J. R.; Todey, D.; Massey, R.; Widhalm, M.; Biehl, L. L.; Andresen, J.

    2014-12-01

    Climate extremes are a major challenge for corn producers in the central United States. Among those extremes are wet springs that lead to planting delays, late spring and early fall frosts that can damage crops, and extreme summer temperatures either too warm or too cool. A newly-operational corn growing degree-day (CGDD) tool helps producers manage and adapt to these extremes. For example, a challenge in recent years has been exceptionally wet springs that have led to significant planting delays. Producers have been forced to re-assess their planting strategies on short notice, such as switching to a faster-growing but lower-yielding hybrids. With this pattern of wetter springs projected to continue or worsen in the central United States, the problem will remain and likely get worse. Another example is helping producers identify the risk of early or late frost/freezes. The CGDD tool puts current conditions into a 30-year historical perspective and offers trend projections (based on climatology or forecasts) through the end of the calendar year. Corn, or sometimes called modified, growing degree-days use a temperature base of 10 C (50 F) and a ceiling of 30 C (86 F) and is strongly correlated with the development of the corn crop. This tool was developed as part of USDA-supported U2U Useful to Usable Project for transforming climate variability and change information for cereal crop producers.

  12. Taiwan: growing, growing, gone.

    PubMed

    Hanson, R

    1979-10-01

    Accommodation between Taiwan and the People's Republic of China may not be inconceivable as trade contacts (though officially disallowed) grow. Because of Taiwan's well-established success and the pressing need in China to industrialize, it appears, however, that such an accommodation will occur only after China becomes more like Taiwan. Taiwan owes its success, first, to land reform and then, in the 1960s, to steady industrialization. Besides broad controls over money supply and capital designed to ward off inflationary pressures when needed, and the grand outlines for development, another factor in the island's economic success is that the government has interfered little with private enterprise. The economy has an underpinning of small to medium size businesses. There are more than 10,000 trading companies. This diverse foundation has given the economy as a whole a flexible buffer on which more sophisticated industires can be formed. PMID:12278253

  13. Seasonal Modulation of Earthquake Swarm Activity Near Maupin, Oregon

    NASA Astrophysics Data System (ADS)

    Braunmiller, J.; Nabelek, J.; Trehu, A. M.

    2012-12-01

    Between December 2006 and November 2011, the Pacific Northwest Seismic Network (PNSN) reported 464 earthquakes in a swarm about 60 km east-southeast of Mt. Hood near the town of Maupin, Oregon. Relocation of forty-five MD≥2.5 earthquakes and regional moment tensor analysis of nine 3.3≤Mw≤3.9 earthquakes reveals a north-northwest trending, less than 1 km2 sized active fault patch on a 70° west dipping fault. At about 17 km depth, the swarm occurred at or close to the bottom of the seismogenic crust. The swarm's cumulative seismic moment release, equivalent to an Mw=4.4 earthquake, is not dominated by a single shock; it is rather mainly due to 20 MD≥3.0 events, which occurred throughout the swarm. The swarm started at the southern end and, during the first 18 months of activity, migrated to the northwest at a rate of about 1-2 m/d until reaching its northern terminus. A 10° fault bend, inferred from locations and fault plane solutions, acted as geometrical barrier that temporarily halted event migration in mid-2007 before continuing north in early 2008. The slow event migration points to a pore pressure diffusion process suggesting the swarm onset was triggered by fluid inflow into the fault zone. At 17 km depth, triggering by meteoritic water seems unlikely for a normal crustal permeability. The double couple source mechanisms preclude a magmatic intrusion at the depth of the earthquakes. However, fluids (or gases) associated with a deeper, though undocumented, magma injection beneath the Cascade Mountains, could trigger seismicity in a pre-stressed region when they have migrated upward and reached the seismogenic crust. Superimposed on overall swarm evolution, we found a statistically significant annual seismicity variation, which is likely surface driven. The annual seismicity peak during spring (March-May) coincides with the maximum snow load on the near-by Cascades. The load corresponds to a surface pressure variation of about 6 kPa, which likely

  14. Using a model and forecasted weather to predict forage and livestock production for making stocking decisions in the coming growing season

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Forecasting peak standing crop (PSC) for the coming grazing season can help ranchers make appropriate stocking decisions to reduce enterprise risks. Previously developed PSC predictors were based on short-term experimental data (<15 yr) and limited stocking rates (SR) without including the effect of...

  15. Seasonal divergence in the interannual responses of Northern Hemisphere vegetation activity to variations in diurnal climate

    PubMed Central

    Wu, Xiuchen; Liu, Hongyan; Li, Xiaoyan; Liang, Eryuan; Beck, Pieter S. A.; Huang, Yongmei

    2016-01-01

    Seasonal asymmetry in the interannual variations in the daytime and nighttime climate in the Northern Hemisphere (NH) is well documented, but its consequences for vegetation activity remain poorly understood. Here, we investigate the interannual responses of vegetation activity to variations of seasonal mean daytime and nighttime climate in NH (>30 °N) during the past decades using remote sensing retrievals, FLUXNET and tree ring data. Despite a generally significant and positive response of vegetation activity to seasonal mean maximum temperature () in ~22–25% of the boreal (>50 °N) NH between spring and autumn, spring-summer progressive water limitations appear to decouple vegetation activity from the mean summer , particularly in climate zones with dry summers. Drought alleviation during autumn results in vegetation recovery from the marked warming-induced drought limitations observed in spring and summer across 24–26% of the temperate NH. Vegetation activity exhibits a pervasively negative correlation with the autumn mean minimum temperature, which is in contrast to the ambiguous patterns observed in spring and summer. Our findings provide new insights into how seasonal asymmetry in the interannual variations in the mean daytime and nighttime climate interacts with water limitations to produce spatiotemporally variable responses of vegetation growth. PMID:26751166

  16. Seasonal divergence in the interannual responses of Northern Hemisphere vegetation activity to variations in diurnal climate.

    PubMed

    Wu, Xiuchen; Liu, Hongyan; Li, Xiaoyan; Liang, Eryuan; Beck, Pieter S A; Huang, Yongmei

    2016-01-11

    Seasonal asymmetry in the interannual variations in the daytime and nighttime climate in the Northern Hemisphere (NH) is well documented, but its consequences for vegetation activity remain poorly understood. Here, we investigate the interannual responses of vegetation activity to variations of seasonal mean daytime and nighttime climate in NH (>30 °N) during the past decades using remote sensing retrievals, FLUXNET and tree ring data. Despite a generally significant and positive response of vegetation activity to seasonal mean maximum temperature (Tmax) in ~22-25% of the boreal (>50 °N) NH between spring and autumn, spring-summer progressive water limitations appear to decouple vegetation activity from the mean summer Tmax, particularly in climate zones with dry summers. Drought alleviation during autumn results in vegetation recovery from the marked warming-induced drought limitations observed in spring and summer across 24-26% of the temperate NH. Vegetation activity exhibits a pervasively negative correlation with the autumn mean minimum temperature, which is in contrast to the ambiguous patterns observed in spring and summer. Our findings provide new insights into how seasonal asymmetry in the interannual variations in the mean daytime and nighttime climate interacts with water limitations to produce spatiotemporally variable responses of vegetation growth.

  17. 76 FR 77554 - Agency Information Collection Activities; Submission for OMB Review; Comment Request; Growing...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-12-13

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF LABOR Office... providing entrepreneurship training services to individuals interested in starting or growing a business..., treatment group members were offered an assessment of their business needs, classroom training,...

  18. Seasonal Variability in Boreal Wildfire Activity Associated with Landscape Patterns of Burned Area

    NASA Astrophysics Data System (ADS)

    Barrett, K. M.; Kasischke, E. S.

    2012-12-01

    Wildfire is the most prominent disturbance in the boreal forest, effecting changes in stand age and vegetation composition often over thousands of square kilometers. The effect of wildfire on ecosystem structure and function depends heavily on the seasonality of the burn, and periods of seasonally high fire activity are highly sporadic. The majority of area in Alaska that burns in a fire season does so during relatively short periods of high fire activity. These periods, which can be determined from active fire detections or fire management agency data records, are caused by elevated air temperatures and low precipitation which decrease fuel moisture and encourage the spread of fire. While fire fronts dominate during periods of low fire activity, more active periods have a higher proportion of residual burning which remains after a front has passed through. Residual burning is likely responsible for the extensive combustion of surface organic materials in the boreal forest, which can lead to post-fire changes in dominant vegetation type. Seasonal variations in fire activity are therefore an important factor in the mosaic of severity conditions across large burned areas and shifts in land cover over successional time scales. The purpose of this study is to characterize the temporal and spatial variability in periods of seasonal high fire activity that influence patterns of burned area. In large burns, unburned areas within a fire scar may serve as an important seed stock during post-fire recruitment. These areas may also feedback to future fire regimes through the preservation of more fire-resistant vegetation in unburned "islands".

  19. The stress of growing old: sex- and season-specific effects of age on allostatic load in wild grey mouse lemurs.

    PubMed

    Hämäläinen, Anni; Heistermann, Michael; Kraus, Cornelia

    2015-08-01

    Chronic stress [i.e. long-term elevation of glucocorticoid (GC) levels] and aging have similar, negative effects on the functioning of an organism. Aged individuals' declining ability to regulate GC levels may therefore impair their ability to cope with stress, as found in humans. The coping of aged animals with long-term natural stressors is virtually unstudied, even though the ability to respond appropriately to stressors is likely integral to the reproduction and survival of wild animals. To assess the effect of age on coping with naturally fluctuating energetic demands, we measured stress hormone output via GC metabolites in faecal samples (fGCM) of wild grey mouse lemurs (Microcebus murinus) in different ecological seasons. Aged individuals were expected to exhibit elevated fGCM levels under energetically demanding conditions. In line with this prediction, we found a positive age effect in the dry season, when food and water availability are low and mating takes place, suggesting impaired coping of aged wild animals. The age effect was significantly stronger in females, the longer-lived sex. Body mass of males but not females correlated positively with fGCM in the dry season. Age or body mass did not influence fGCM significantly in the rainy season. The sex- and season-specific predictors of fGCM may reflect the differential investment of males and females into reproduction and longevity. A review of prior research indicates contradictory aging patterns in GC regulation across and even within species. The context of sampling may influence the likelihood of detecting senescent declines in GC functioning.

  20. Evaluation of bactericidal activity of Hannon honey on slowly growing bacteria in the chemostat.

    PubMed

    Sufya, Najib; Matar, Noora; Kaddura, Rawanda; Zorgani, Abdulaziz

    2014-01-01

    There is renewed interest in the therapeutic use of honey, including use in the treatment of infected wounds and burn patients. In this study, we have assessed the antibacterial activity of Libyan floral Hannon honey on Escherichia coli and Staphylococcus aureus, both known to infect wounds. The effects of four concentrations (5%-30%) of honey were compared with that of four antibiotics (ampicillin, tetracycline, polymyxin, and ciprofloxacin) on the growth of these bacteria at early log, mid log, and late log phases. It has been shown that E. coli and S. aureus are to some degree susceptible during mid log phase compared with late log phase, demonstrated by their complete resistance to antibiotics. Chemostat culture was used to investigate the effect of honey on E. coli grown at a steady state with specific growth rates between 0.1 to 0.5 hour(-1). The rate of killing was distinctively clear during the two stages of growth monitored: there was a relatively moderate reduction at the slow growth phase (0.1 to 0.3 hour(-1)), while a dramatic reduction was obtained at the fast growth phase (0.3 to 0.5 hour(-1)), reaching a complete reduction at 0.5 hour(-1). These results complement data using the cup-cut technique. The antibacterial effect of honey was concentration and time dependent, the bactericidal effect was indeed observed at low concentrations, it demonstrates that the honey has more impact on slow growing bacteria than antibiotics have. We suggest that more reduction could be achieved at higher concentrations of honey. These results may have important clinical implications, such as for the management of wound and burn patients. PMID:25342919

  1. Evaluation of bactericidal activity of Hannon honey on slowly growing bacteria in the chemostat

    PubMed Central

    Sufya, Najib; Matar, Noora; Kaddura, Rawanda; Zorgani, Abdulaziz

    2014-01-01

    There is renewed interest in the therapeutic use of honey, including use in the treatment of infected wounds and burn patients. In this study, we have assessed the antibacterial activity of Libyan floral Hannon honey on Escherichia coli and Staphylococcus aureus, both known to infect wounds. The effects of four concentrations (5%–30%) of honey were compared with that of four antibiotics (ampicillin, tetracycline, polymyxin, and ciprofloxacin) on the growth of these bacteria at early log, mid log, and late log phases. It has been shown that E. coli and S. aureus are to some degree susceptible during mid log phase compared with late log phase, demonstrated by their complete resistance to antibiotics. Chemostat culture was used to investigate the effect of honey on E. coli grown at a steady state with specific growth rates between 0.1 to 0.5 hour−1. The rate of killing was distinctively clear during the two stages of growth monitored: there was a relatively moderate reduction at the slow growth phase (0.1 to 0.3 hour−1), while a dramatic reduction was obtained at the fast growth phase (0.3 to 0.5 hour−1), reaching a complete reduction at 0.5 hour−1. These results complement data using the cup-cut technique. The antibacterial effect of honey was concentration and time dependent, the bactericidal effect was indeed observed at low concentrations, it demonstrates that the honey has more impact on slow growing bacteria than antibiotics have. We suggest that more reduction could be achieved at higher concentrations of honey. These results may have important clinical implications, such as for the management of wound and burn patients. PMID:25342919

  2. An Estimate of the North Atlantic Basin Tropical Cyclone Activity for the 2010 Hurricane Season

    NASA Technical Reports Server (NTRS)

    Wilson, Robert M.

    2010-01-01

    Estimates are presented for the tropical cyclone activity expected for the 2010 North Atlantic basin hurricane season. It is anticipated that the 2010 season will be more active than the 2009 season, reflecting increased frequencies more akin to that of the current more active phase that has been in vogue since 1995. Averages (+/- 1 sd) during the current more active phase are 14.5+/-4.7, 7.8+/-3.2, 3.7+/-1.8, and 2+/- 2, respectively, for the number of tropical cyclones (NTC), the number of hurricanes (NH), the number of major hurricanes (NMH), and the number of United States (U.S.) land-falling hurricanes (NUSLFH). Based on the "usual" behavior of the 10-yma parametric first differences, one expects NTC = 19+/-2, NH = 14+/-2, NMH = 7+/-2, and NUSLFH = 4+/-2 for the 2010 hurricane season; however, based on the "best guess" 10-yma values of surface-air temperature at the Armagh Observatory (Northern Ireland) and the Oceanic Nino Index, one expects NTC > or equals 16, NH > or equals 14, NMH > or equals 7, and NUSLFH > or equals 6.

  3. Seasonal variation in physical activity and sedentary time in different European regions. The HELENA study.

    PubMed

    Gracia-Marco, Luis; Ortega, Francisco B; Ruiz, Jonatan R; Williams, Craig A; Hagströmer, Maria; Manios, Yannis; Kafatos, Anthony; Béghin, Laurent; Polito, Angela; De Henauw, Stefaan; Valtueña, Jara; Widhalm, Kurt; Molnar, Denes; Alexy, Ute; Moreno, Luis A; Sjöström, Michael

    2013-01-01

    This report aims (1) to examine the association between seasonality and physical activity (PA) and sedentary time in European adolescents and (2) to investigate whether this association was influenced by geographical location (Central-North versus South of Europe), which implies more or less extreme weather and daylight hours. Valid data on PA, sedentary time and seasonality were obtained in 2173 adolescents (1175 females; 12.5-17.5 years) included in this study. Physical activity and sedentary time were measured by accelerometers. ANCOVA was conducted to analyse the differences in PA and sedentary time across seasons. Results showed that girls had lower levels of moderate to vigorous PA (MVPA) and average PA, and spent more time in sedentary activities in winter compared with spring (all P < 0.05). Stratified analyses showed differences in PA and sedentary time between winter and spring in European girls from Central-North of Europe (P < 0.05 for sedentary time). There were no differences between PA and sedentary time across seasonality in boys. In conclusion, winter is related with less time spent in MVPA, lower average PA and higher time spent in sedentary activities in European adolescent girls, compared with spring. These differences seem to mainly occur in Central-North Europe.

  4. Improving in-season nitrogen recommendations for maize using an active sensor

    Technology Transfer Automated Retrieval System (TEKTRAN)

    An active crop canopy reflectance sensor could be used to increase N-use efficiency in corn (Zea mays L.), if temporal and spatial variability in soil N availability and plant demand are adequately accounted for with an in-season N application. Our objective was to evaluate the success of using an a...

  5. Seasonal Variation in Children’s Physical Activity and Sedentary Time

    PubMed Central

    Atkin, Andrew J; Sharp, Stephen J; Harrison, Flo; Brage, Søren; van Sluijs, Esther MF

    2015-01-01

    Purpose Understanding seasonal variation in physical activity is important for informing public health surveillance and intervention design. The aim of the current study was to describe seasonal variation in children’s objectively measured physical activity and sedentary time. Methods Data are from the UK Millennium Cohort Study. Participants were invited to wear an accelerometer for seven days on five occasions between November 2008 and January 2010. Outcome variables were sedentary time (<100 counts per minute; min/day) and moderate to vigorous physical activity (MVPA; >2241 counts per min; min/day). Season was characterised using a categorical variable (spring, summer, autumn, winter) and a continuous function of day of year. Cross-classified linear regression models were used to estimate the association of each of these constructs with the outcome variables. Modification of the seasonal variation by sex, weight status, urban/rural location, parental income and day of the week (week/weekend) was examined using interaction terms in regression models. Results At least 1 wave of valid accelerometer data was obtained from 704 participants (47% male; baseline age 7.6(0.3) years). MVPA was lower in autumn and winter relative to spring, with the magnitude of this difference varying by week/weekend day, sex, weight status, urban/rural location and family income (p for interaction <0.05 in all cases). Total sedentary time was greater in autumn and winter compared to spring; the seasonal effect was stronger at the weekend than during the week (p for interaction <0.01). Conclusion Lower levels of MVPA and elevated sedentary time support the implementation of intervention programmes during autumn and winter. Evidence of greater seasonal variation in weekend behaviour and amongst certain socio-demographic subgroups highlights targets for tailored intervention programmes. PMID:26429733

  6. Seasonal variations in sexual activity and their implications for sexual health promotion.

    PubMed

    Wellings, K; Macdowall, W; Catchpole, M; Goodrich, J

    1999-02-01

    Although seasonal variations in births are observed in all human populations, the links between calendar events and sexual activity have received little attention in relation to health promotion and service provision. We have plotted various relevant data--routinely collected data for births within and outside of marriage, abortions, sexually transmitted infections, human immunodeficiency virus tests and condom sales figures--by calendar period. The trends point consistently to an increase in sexual activity and unsafe sex occurring at or around the Christmas period, and a longer but less pronounced subsidiary period of increased sexual activity and unsafe sex coinciding with the summer vacation. We conclude that seasonal patterns of sexual activity have implications for provision of sexual health services and for the timing and targeting of sexual health promotional interventions.

  7. Effects of seasonal variation in prey abundance on field metabolism, water flux, and activity of a tropical ambush foraging snake.

    PubMed

    Christian, Keith; Webb, Jonathan K; Schultz, Timothy; Green, Brian

    2007-01-01

    The responses of animals to seasonal food shortages can have important consequences for population dynamics and the structure and function of food webs. We investigated how an ambush foraging snake, the northern death adder Acanthophis praelongus, responds to seasonal fluctuations in prey availability in its tropical environment. In the dry season, field metabolic rates and water flux, as measured by doubly labeled water, were significantly lower than in the wet season. Unlike some other reptiles of the wet-dry tropics, death adders showed no seasonal difference in their resting metabolism. About 94% of the decrease in energy expended in the dry season was due to a decrease in activity and digestion, with lower body temperatures accounting for the remainder. In the dry season, death adders were less active and moved shorter distances between foraging sites than in the wet season. Analysis of energy expenditure suggested that adders fed no more than every 2-3 wk in the dry season but fed more frequently during the wet season. Unlike many lizards that cease feeding during the dry season, death adders remain active and attempt to maximize their energy intake year-round.

  8. Influence of harvest season on antioxidant activity and constituents of rabbiteye blueberry ( Vaccinium ashei ) leaves.

    PubMed

    Zhu, Liancai; Liu, Xi; Tan, Jun; Wang, Bochu

    2013-11-27

    To select rabbiteye blueberry leaves from an appropriate harvest season to develop functional foods, this paper studied the bioactive secondary metabolites and the antioxidant capacity of rabbiteye blueberry leaves from May, September, and November. The results showed the leaves from May had the highest content of total flavonoids (114.21 mg/g) and the leaves from November had the highest content of total polyphenols and proanthocyanidins (425.24 and 243.29 mg/g, respectively). It was further found that blueberry leaves from different seasons have similar bioactive constituents, but their contents are obviously different by HPLC. The rabbiteye blueberry leaves from November had the highest antioxidant capacity, which was well correlated with their highest proanthocyanidin content. The results clarify that the blueberry leaves from different seasons have different contents of bioactive secondary metabolites and different antioxidant activities, which implied that leaves from November should be selected first for utilization in functional foods.

  9. Antileishmanial activity of the essential oil from Tetradenia riparia obtained in different seasons.

    PubMed

    Cardoso, Bruna Muller; de Mello, Tatiane França Perles; Lopes, Sara Negrão; Demarchi, Izabel Galhardo; Lera, Daniele Stefani Lopes; Pedroso, Raíssa Bocchi; Cortez, Diogenes Aparício; Gazim, Zilda Cristiani; Aristides, Sandra Mara Alessi; Silveira, Thais Gomes Verzignassi; Lonardoni, Maria Valdrinez Campana

    2015-12-01

    The herbaceous shrub Tetradenia riparia has been traditionally used to treat inflammatory and infectious diseases. Recently, a study showed that T. riparia essential oil (TrEO) obtained in summer has antileishmanial effects, although these results could be influenced by seasonal variation. This study evaluated the activity of the TrEO obtained in different seasons against Leishmania (Leishmania) amazonensis, in vitro and in vivo. The compounds in the TrEO were analysed by gas chromatography-mass spectrometry; terpenoids were present and oxygenated sesquiterpenes were the majority compounds (55.28%). The cytotoxicity and nitric oxide (NO) production were also tested after TrEO treatment. The TrEO from all seasons showed a 50% growth inhibitory concentration for promastigotes of about 15 ng/mL; at 30 ng/mL and 3 ng/mL, the TrEO reduced intracellular amastigote infection, independently of season. The TrEO from plants harvested in summer had the highest 50% cytotoxic concentration, 1,476 ng/mL for J774.A1 macrophages, and in spring (90.94 ng/mL) for murine macrophages. NO production did not change in samples of the TrEO from different seasons. The antileishmanial effect in vivo consisted of a reduction of the parasite load in the spleen. These results suggest that the TrEO has potential effects on L. (L.) amazonensis, consonant with its traditional use to treat parasitic diseases.

  10. Antileishmanial activity of the essential oil from Tetradenia riparia obtained in different seasons.

    PubMed

    Cardoso, Bruna Muller; de Mello, Tatiane França Perles; Lopes, Sara Negrão; Demarchi, Izabel Galhardo; Lera, Daniele Stefani Lopes; Pedroso, Raíssa Bocchi; Cortez, Diogenes Aparício; Gazim, Zilda Cristiani; Aristides, Sandra Mara Alessi; Silveira, Thais Gomes Verzignassi; Lonardoni, Maria Valdrinez Campana

    2015-12-01

    The herbaceous shrub Tetradenia riparia has been traditionally used to treat inflammatory and infectious diseases. Recently, a study showed that T. riparia essential oil (TrEO) obtained in summer has antileishmanial effects, although these results could be influenced by seasonal variation. This study evaluated the activity of the TrEO obtained in different seasons against Leishmania (Leishmania) amazonensis, in vitro and in vivo. The compounds in the TrEO were analysed by gas chromatography-mass spectrometry; terpenoids were present and oxygenated sesquiterpenes were the majority compounds (55.28%). The cytotoxicity and nitric oxide (NO) production were also tested after TrEO treatment. The TrEO from all seasons showed a 50% growth inhibitory concentration for promastigotes of about 15 ng/mL; at 30 ng/mL and 3 ng/mL, the TrEO reduced intracellular amastigote infection, independently of season. The TrEO from plants harvested in summer had the highest 50% cytotoxic concentration, 1,476 ng/mL for J774.A1 macrophages, and in spring (90.94 ng/mL) for murine macrophages. NO production did not change in samples of the TrEO from different seasons. The antileishmanial effect in vivo consisted of a reduction of the parasite load in the spleen. These results suggest that the TrEO has potential effects on L. (L.) amazonensis, consonant with its traditional use to treat parasitic diseases. PMID:26602873

  11. Antileishmanial activity of the essential oil from Tetradenia riparia obtained in different seasons

    PubMed Central

    Cardoso, Bruna Muller; de Mello, Tatiane França Perles; Lopes, Sara Negrão; Demarchi, Izabel Galhardo; Lera, Daniele Stefani Lopes; Pedroso, Raíssa Bocchi; Cortez, Diogenes Aparício; Gazim, Zilda Cristiani; Aristides, Sandra Mara Alessi; Silveira, Thais Gomes Verzignassi; Lonardoni, Maria Valdrinez Campana

    2015-01-01

    The herbaceous shrub Tetradenia riparia has been traditionally used to treat inflammatory and infectious diseases. Recently, a study showed that T. riparia essential oil (TrEO) obtained in summer has antileishmanial effects, although these results could be influenced by seasonal variation. This study evaluated the activity of the TrEO obtained in different seasons against Leishmania (Leishmania) amazonensis, in vitro and in vivo. The compounds in the TrEO were analysed by gas chromatography-mass spectrometry; terpenoids were present and oxygenated sesquiterpenes were the majority compounds (55.28%). The cytotoxicity and nitric oxide (NO) production were also tested after TrEO treatment. The TrEO from all seasons showed a 50% growth inhibitory concentration for promastigotes of about 15 ng/mL; at 30 ng/mL and 3 ng/mL, the TrEO reduced intracellular amastigote infection, independently of season. The TrEO from plants harvested in summer had the highest 50% cytotoxic concentration, 1,476 ng/mL for J774.A1 macrophages, and in spring (90.94 ng/mL) for murine macrophages. NO production did not change in samples of the TrEO from different seasons. The antileishmanial effect in vivo consisted of a reduction of the parasite load in the spleen. These results suggest that the TrEO has potential effects on L. (L.) amazonensis, consonant with its traditional use to treat parasitic diseases. PMID:26602873

  12. Views of Growing Methane Emissions near Oil and Natural Gas Activity: Satellite, Aircraft, and Ground

    NASA Astrophysics Data System (ADS)

    Kollonige, D. E.; Thompson, A. M.; Diskin, G. S.; Hannigan, J. W.; Nussbaumer, E.

    2015-12-01

    To better understand the discrepancies between current top-down and bottom-up estimates, additional methane (CH4) measurements are necessary for regions surrounding growing oil and natural gas (ONG) development. We have evaluated satellite measurements of CH4 in US regions with ONG operations for their application as "top-down" constraints (part of the NASA Air Quality Applied Sciences Team (AQAST) project). For validation of the satellite instruments' sensitivities to emitted gases, we focus on regions where the DISCOVER-AQ (Deriving Information on Surface Conditions from Column and Vertically Resolved Observations Relevant to Air Quality) campaign deployed ground and aircraft measurements in Maryland (2011), California and Texas (2013), and Colorado (2014). The largest CH4 signals were observed in the Greater Green River and Powder River Basins using Tropospheric Emission Spectrometer (TES) Representative Tropospheric Volume Mixing Ratio (RTVMR) measurements. A long-term comparison between a ground remote-sensing Fourier Transform Spectrometer (FTS) at Boulder and TES for 2010-2013 shows good correlation and differences ranging 2.5-5% for their yearly distribution of total column CH4. To determine any correlation between lower/mid-tropospheric CH4 (where a thermal IR sensor, such as TES, is most sensitive) and near-surface/boundary CH4 (where sources emit), we analyze the variability of DISCOVER-AQ aircraft profiles using principal component analysis and assess the correlation between near-surface (0-2 km) and mid-tropospheric (>2 km) CH4 concentrations. Using these relationships, we estimate near-surface CH4 using mid-tropospheric satellite measurements based on the partial column amounts within vertical layers with a linear regression. From this analysis, we will demonstrate whether the uncertainties of satellite-estimated near-surface CH4 are comparable to observed variability near ONG activity. These results will assist validation of satellite instrument

  13. Seasonal variation in American black bear Ursus americanus activity patterns: Quantification via remote photography

    USGS Publications Warehouse

    Bridges, A.S.; Vaughan, M.R.; Klenzendorf, S.

    2004-01-01

    Activity pattern plasticity may serve as an evolutionary adaptation to optimize fitness in an inconstant environment, however, quantifying patterns and demonstrating variation can be problematic. For American black bears Ursus americanus, wariness and habitat inaccessibility further complicate quantification. Radio telemetry has been the primary technique used to examine activity, however, interpretation error and limitation on numbers of animals available to monitor prevent extrapolation to unmarked or untransmittered members of the population. We used remote cameras to quantify black bear activity patterns and examined differences by season, sex and reproductive class in the Alleghany Mountains of western Virginia, USA. We used 1,533 pictures of black bears taken during 1998-2002 for our analyses. Black bears generally were diurnal in summer and nocturnal in autumn with a vespertine activity peak during both seasons. Bear-hound training seasons occurred during September and may offer explanation for the observed shift towards nocturnal behaviour. We found no substantial differences in activity patterns between sex and reproductive classes. Use of remote cameras allowed us to efficiently sample larger numbers of individual animals and likely offered a better approximation of population-level activity patterns than individual-level, telemetry-based methodologies.

  14. Agriculture--Ornamental Horticulture. Building Model Greenhouse and Growing Plants. Kit No. 41. Instructor's Manual [and] Student Learning Activity Guide.

    ERIC Educational Resources Information Center

    Carter, Wesley

    An instructor's manual and student activity guide on building a model greenhouse and growing plants are provided in this set of prevocational education materials which focuses on the vocational area of agriculture (ornamental horticulture). (This set of materials is one of ninety-two prevocational education sets arranged around a cluster of seven…

  15. Real-time Prescription Surveillance and its Application to Monitoring Seasonal Influenza Activity in Japan

    PubMed Central

    Ohkusa, Yasushi; Ibuka, Yoko; Kawanohara, Hirokazu; Taniguchi, Kiyosu; Okabe, Nobuhiko

    2012-01-01

    Background Real-time surveillance is fundamental for effective control of disease outbreaks, but the official sentinel surveillance in Japan collects information related to disease activity only weekly and updates it with a 1-week time lag. Objective To report on a prescription surveillance system using electronic records related to prescription drugs that was started in 2008 in Japan, and to evaluate the surveillance system for monitoring influenza activity during the 2009–2010 and 2010–2011 influenza seasons. Methods We developed an automatic surveillance system using electronic records of prescription drug purchases collected from 5275 pharmacies through the application service provider’s medical claims service. We then applied the system to monitoring influenza activity during the 2009–2010 and 2010–2011 influenza seasons. The surveillance system collected information related to drugs and patients directly and automatically from the electronic prescription record system, and estimated the number of influenza cases based on the number of prescriptions of anti-influenza virus medication. Then it shared the information related to influenza activity through the Internet with the public on a daily basis. Results During the 2009–2010 influenza season, the number of influenza patients estimated by the prescription surveillance system between the 28th week of 2009 and the 12th week of 2010 was 9,234,289. In the 2010–2011 influenza season, the number of influenza patients between the 36th week of 2010 and the 12th week of 2011 was 7,153,437. The estimated number of influenza cases was highly correlated with that predicted by the official sentinel surveillance (r = .992, P < .001 for 2009–2010; r = .972, P < .001 for 2010–2011), indicating that the prescription surveillance system produced a good approximation of activity patterns. Conclusions Our prescription surveillance system presents great potential for monitoring influenza activity and for

  16. Exploring children's seasonal play to promote active lifestyles in Auckland, New Zealand.

    PubMed

    Ergler, Christina R; Kearns, Robin; Witten, Karen

    2016-09-01

    Studies of seasonal barriers for outdoor activities seldom view families' play practices as grounded in the everyday experience of the natural elements. This paper brings 20 families' mundane outdoor play experiences in Auckland's temperate climate to the fore. Through drawings and interviews, families residing in both suburban detached houses and central city apartments revealed locally constituted beliefs about appropriate play spaces (e.g. garden, park). While the majority of participants retreated to indoor activities during winter, some children and their parents viewed the outdoors as the only opportunity for 'real fun'. We advocate the importance of a better understanding of children's seasonal outdoor play. In particular, we argue that in order to promote year-round healthy levels of outdoor activities it is necessary to understand variations in societal, neighbourhood and family values attributed to outdoor activities. Further, to develop a more nuanced understanding of the locational complexities of outdoor play it is important to understand the meanings of, and practices associated with, seasonal and weather conditions in different international locations. PMID:27572547

  17. Seasonal, daily activity, and habitat use by three sympatric pit vipers (Serpentes, Viperidae) from southern Brazil.

    PubMed

    Rocha, Marcelo C; Hartmann, Paulo A; Winck, Gisele R; Cechin, Sonia Z

    2014-04-25

    Viperid snakes are widely distributed in the South America and the greater distribution range of the family is found at the Crotalinae subfamily. Despite the abundance of this snakes along their geographic distribution, some ecological aspects remain unknown, principally at subtropical areas. In the present study, we evaluated the activity (daily and seasonal) and the use of the habitat by Bothrops diporus, B. jararaca and B. jararacussu, in an Atlantic Forest area at southern Brazil. We observed higher incidence of viperid snakes during the months with higher temperatures, while no snakes were found during the months with lower temperatures. The data suggest the minimum temperature as environmental variable with the greatest influence on the seasonal activity of this species. Considering the daily activity, we observed a tendency of snakes to avoid the warmest hours. Bothrops jararacussu tend to avoid open areas, being registered only inside and at the edges of the forest. We compared our results with previous studies realized at tropical areas and we suggest the observed seasonal activity as an evolutive response, despite the influence of the different environmental variables, according to the occurence region.

  18. Seasonal 7Be and 137Cs activities in surface air before and after the Chernobyl event.

    PubMed

    Kulan, A

    2006-01-01

    Seasonal fluctuations of cosmogenic (7)Be (T(1/2)=53.4 days) and anthropogenic (137)Cs (T(1/2)=30 years) activities in surface air (aerosols) have been extracted from a long data record (1972-2000) at high latitude (56 degrees N-68 degrees N, Sweden). Normalization to weekly average values was used to control long-term trends so that cyclical trends could be investigated. Enhanced (7)Be activity was observed in spring and summer seasons and likely relates to the seasonal thinning of the tropopause. Variations in the (137)Cs activity record seem to reflect how the isotope was injected in the atmosphere (stratospheric from bomb tests and tropospheric from the Chernobyl accident) and subsequent transport mechanisms. Accordingly, until 1986, the surface air (137)Cs activity was strongly related to nuclear weapons test fallout and exhibits temporal fluctuations resembling the (7)Be. Conversely, since 1986 the Chernobyl-produced (137)Cs dominates the long-term record that shows annual cycles that are strongly controlled by atmospheric boundary layer conditions. Additionally, short-term data within the post-Chernobyl period suggest subtle intrusion of air masses rich in (137)Cs that may occur throughout the year, and differences resulting from spatial occurrence at these latitudes. This is an important observation that may have to do with year-to-year variation and calls for caution when interpreting short-term data records. PMID:16876295

  19. Comparative analysis of antioxidant activity and functional components of the ethanol extract of lotus (Nelumbo nucifera) from various growing regions.

    PubMed

    Zhao, Xu; Shen, Jian; Chang, Kyung Ja; Kim, Sung Hoon

    2014-07-01

    The variations in antioxidant activity and concentration of functional components in the ethanol extracts of lotus seeds and rhizomes based on the growing region and dryness were investigated. Free radical scavenging activity, total phenolic and flavonoid content, and concentration of several specific flavonoids and alkaloids in the ethanol extracts of lotus were measured. Antioxidant activity and its correlative total phenolic content varied characteristically depending on the growing region and dryness. High-perfomance liquid chromatography analysis showed that the ethanol extracts of lotus seeds from Vietnam (Ho Chi Minh City), raw rhizomes from Korea (Siheung), and dried rhizomes from Japan (Nigata) had the greatest specific flavonoid content. The ethanol extracts of seeds from China (Hubei), raw rhizomes from Japan (Nigata), and dried rhizomes from Korea (Siheung) had the greatest specific alkaloid content. Astragaline, rutin, isoquercetin, nuciferine, dauricine, isoliensinine, and neferine were identified in lotus rhizomes for the first time in this study.

  20. Influenza Activity - United States, 2015-16 Season and Composition of the 2016-17 Influenza Vaccine.

    PubMed

    Davlin, Stacy L; Blanton, Lenee; Kniss, Krista; Mustaquim, Desiree; Smith, Sophie; Kramer, Natalie; Cohen, Jessica; Cummings, Charisse Nitura; Garg, Shikha; Flannery, Brendan; Fry, Alicia M; Grohskopf, Lisa A; Bresee, Joseph; Wallis, Teresa; Sessions, Wendy; Garten, Rebecca; Xu, Xiyan; Elal, Anwar Isa Abd; Gubareva, Larisa; Barnes, John; Wentworth, David E; Burns, Erin; Katz, Jacqueline; Jernigan, Daniel; Brammer, Lynnette

    2016-01-01

    During the 2015-16 influenza season (October 4, 2015-May 21, 2016) in the United States, influenza activity* was lower and peaked later compared with the previous three seasons (2012-13, 2013-14, and 2014-15). Activity remained low from October 2015 until late December 2015 and peaked in mid-March 2016. During the most recent 18 influenza seasons (including this season), only two other seasons have peaked in March (2011-12 and 2005-06). Overall influenza activity was moderate this season, with a lower percentage of outpatient visits for influenza-like illness (ILI),(†) lower hospitalization rates, and a lower percentage of deaths attributed to pneumonia and influenza (P&I) compared with the preceding three seasons. Influenza A(H1N1)pdm09 viruses predominated overall, but influenza A(H3N2) viruses were more commonly identified from October to early December, and influenza B viruses were more commonly identified from mid-April through mid-May. The majority of viruses characterized this season were antigenically similar to the reference viruses representing the recommended components of the 2015-16 Northern Hemisphere influenza vaccine (1). This report summarizes influenza activity in the United States during the 2015-16 influenza season (October 4, 2015-May 21, 2016)(§) and reports the vaccine virus components recommended for the 2016-17 Northern Hemisphere influenza vaccines. PMID:27281364

  1. Xylogenesis: Coniferous Trees of Temperate Forests Are Listening to the Climate Tale during the Growing Season But Only Remember the Last Words!

    PubMed

    Cuny, Henri E; Rathgeber, Cyrille B K

    2016-05-01

    The complex inner mechanisms that create typical conifer tree-ring structure (i.e. the transition from large, thin-walled earlywood cells to narrow, thick-walled latewood cells) were recently unraveled. However, what physiological or environmental factors drive xylogenesis key processes remain unclear. Here, we aim to quantify the influence of seasonal variations in climatic factors on the spectacular changes in the kinetics of wood cell differentiation and in the resulting tree-ring structure. Wood formation was monitored in three sites over 3 years for three coniferous species (Norway spruce [Picea abies], Scots pine [Pinus sylvestris], and silver fir [Abies alba]). Cell differentiation rates and durations were calculated and related to tracheid final dimensions and corresponding climatic conditions. On the one hand, we found that the kinetics of cell enlargement and the final size of the tracheids were not explained by the seasonal changes in climatic factors. On the other hand, decreasing temperatures strongly constrained cell wall deposition rates during latewood formation. However, the influence of temperature was permanently written into tree-ring structure only for the very last latewood cells, when the collapse of the rate of wall deposition was no longer counterbalanced by the increase of its duration. Our results show that the formation of the typical conifer tree-ring structure, in normal climatic conditions, is only marginally driven by climate, suggesting strong developmental control of xylogenesis. The late breakage of the compensatory mechanism at work in the wall deposition process appears as a clue to understand the capacity of the maximum latewood density to record past temperature conditions. PMID:27208048

  2. Predicting Atlantic seasonal hurricane activity using outgoing longwave radiation over Africa

    NASA Astrophysics Data System (ADS)

    Karnauskas, Kristopher B.; Li, Laifang

    2016-07-01

    Seasonal hurricane activity is a function of the amount of initial disturbances (e.g., easterly waves) and the background environment in which they develop into tropical storms (i.e., the main development region). Focusing on the former, a set of indices based solely upon the meridional structure of satellite-derived outgoing longwave radiation (OLR) over the African continent are shown to be capable of predicting Atlantic seasonal hurricane activity with very high rates of success. Predictions of named storms based on the July OLR field and trained only on the time period prior to the year being predicted yield a success rate of 87%, compared to the success rate of NOAA's August outlooks of 53% over the same period and with the same average uncertainty range (±2). The resulting OLR indices are statistically robust, highly detectable, physically linked to the predictand, and may account for longer-term observed trends.

  3. Weekly antibiotic prescribing and influenza activity in Sweden: a study throughout five influenza seasons.

    PubMed

    Ganestam, Frida; Lundborg, Cecilia Stålsby; Grabowska, Katarzyna; Cars, Otto; Linde, Annika

    2003-01-01

    Influenza often leads to bacterial complications that require treatment. It may also be confused with bacterial respiratory infections, leading to unnecessary prescription of antibiotics. In this first study on the relationship between influenza and antibiotic utilization for a whole country, weekly data on verified influenza cases in Sweden were compared to weekly sales of antibiotics for 5 influenza seasons 1997-2002. The peak of influenza activity occurred during the winter. In 4 out of the 5 monitored influenza seasons it occurred in February-March. The fluctuation of antibiotic utilization was relatively constant over the years with peaks before Christmas and in February-March. There were no obvious differences in the total amount of antibiotics dispensed over the years that could be related to influenza activity, but a coincidental relationship between the peaks of diagnosed influenza cases and the peaks of antibiotic utilization was indicated, especially for older age groups.

  4. Seasonality and daily flight activity of stable flies (Diptera: Muscidae) on dairy farms in Saraburi Province, Thailand

    PubMed Central

    Phasuk, Jumnongjit; Prabaripai, Atchariya; Chareonviriyaphap, Theeraphap

    2013-01-01

    Knowledge of seasonal abundance and flight activity patterns are required to design effective management programs for insect pests of humans and livestock. In this study, the seasonality and daily flight activity of Stomoxys species were observed on two dairy farms in Saraburi Province, Thailand. Data were assessed throughout 1 year using Vavoua traps from September 2010 to August 2011. A total of 2,520 individuals belonging to four species were collected. Most Stomoxys species peaked in September (rainy season) and gradually decreased in number toward February (dry season); a second peak occurred between March and April (hot season). Stomoxys calcitrans was caught throughout the year and was the most abundant species in this study. The total number of males and females of S. calcitrans differed significantly among seasons and time intervals. The weather parameters of relative humidity and light intensity were significantly correlated with S. calcitrans abundance. PMID:23673316

  5. Spatio-temporal reconstruction of air temperature maps and their application to estimate rice growing season heat accumulation using multi-temporal MODIS data.

    PubMed

    Zhang, Li-wen; Huang, Jing-feng; Guo, Rui-fang; Li, Xin-xing; Sun, Wen-bo; Wang, Xiu-zhen

    2013-02-01

    The accumulation of thermal time usually represents the local heat resources to drive crop growth. Maps of temperature-based agro-meteorological indices are commonly generated by the spatial interpolation of data collected from meteorological stations with coarse geographic continuity. To solve the critical problems of estimating air temperature (T(a)) and filling in missing pixels due to cloudy and low-quality images in growing degree days (GDDs) calculation from remotely sensed data, a novel spatio-temporal algorithm for T(a) estimation from Terra and Aqua moderate resolution imaging spectroradiometer (MODIS) data was proposed. This is a preliminary study to calculate heat accumulation, expressed in accumulative growing degree days (AGDDs) above 10 °C, from reconstructed T(a) based on MODIS land surface temperature (LST) data. The verification results of maximum T(a), minimum T(a), GDD, and AGDD from MODIS-derived data to meteorological calculation were all satisfied with high correlations over 0.01 significant levels. Overall, MODIS-derived AGDD was slightly underestimated with almost 10% relative error. However, the feasibility of employing AGDD anomaly maps to characterize the 2001-2010 spatio-temporal variability of heat accumulation and estimating the 2011 heat accumulation distribution using only MODIS data was finally demonstrated in the current paper. Our study may supply a novel way to calculate AGDD in heat-related study concerning crop growth monitoring, agricultural climatic regionalization, and agro-meteorological disaster detection at the regional scale.

  6. Spatio-temporal reconstruction of air temperature maps and their application to estimate rice growing season heat accumulation using multi-temporal MODIS data*

    PubMed Central

    Zhang, Li-wen; Huang, Jing-feng; Guo, Rui-fang; Li, Xin-xing; Sun, Wen-bo; Wang, Xiu-zhen

    2013-01-01

    The accumulation of thermal time usually represents the local heat resources to drive crop growth. Maps of temperature-based agro-meteorological indices are commonly generated by the spatial interpolation of data collected from meteorological stations with coarse geographic continuity. To solve the critical problems of estimating air temperature (T a) and filling in missing pixels due to cloudy and low-quality images in growing degree days (GDDs) calculation from remotely sensed data, a novel spatio-temporal algorithm for T a estimation from Terra and Aqua moderate resolution imaging spectroradiometer (MODIS) data was proposed. This is a preliminary study to calculate heat accumulation, expressed in accumulative growing degree days (AGDDs) above 10 °C, from reconstructed T a based on MODIS land surface temperature (LST) data. The verification results of maximum T a, minimum T a, GDD, and AGDD from MODIS-derived data to meteorological calculation were all satisfied with high correlations over 0.01 significant levels. Overall, MODIS-derived AGDD was slightly underestimated with almost 10% relative error. However, the feasibility of employing AGDD anomaly maps to characterize the 2001–2010 spatio-temporal variability of heat accumulation and estimating the 2011 heat accumulation distribution using only MODIS data was finally demonstrated in the current paper. Our study may supply a novel way to calculate AGDD in heat-related study concerning crop growth monitoring, agricultural climatic regionalization, and agro-meteorological disaster detection at the regional scale. PMID:23365013

  7. Spatio-temporal reconstruction of air temperature maps and their application to estimate rice growing season heat accumulation using multi-temporal MODIS data.

    PubMed

    Zhang, Li-wen; Huang, Jing-feng; Guo, Rui-fang; Li, Xin-xing; Sun, Wen-bo; Wang, Xiu-zhen

    2013-02-01

    The accumulation of thermal time usually represents the local heat resources to drive crop growth. Maps of temperature-based agro-meteorological indices are commonly generated by the spatial interpolation of data collected from meteorological stations with coarse geographic continuity. To solve the critical problems of estimating air temperature (T(a)) and filling in missing pixels due to cloudy and low-quality images in growing degree days (GDDs) calculation from remotely sensed data, a novel spatio-temporal algorithm for T(a) estimation from Terra and Aqua moderate resolution imaging spectroradiometer (MODIS) data was proposed. This is a preliminary study to calculate heat accumulation, expressed in accumulative growing degree days (AGDDs) above 10 °C, from reconstructed T(a) based on MODIS land surface temperature (LST) data. The verification results of maximum T(a), minimum T(a), GDD, and AGDD from MODIS-derived data to meteorological calculation were all satisfied with high correlations over 0.01 significant levels. Overall, MODIS-derived AGDD was slightly underestimated with almost 10% relative error. However, the feasibility of employing AGDD anomaly maps to characterize the 2001-2010 spatio-temporal variability of heat accumulation and estimating the 2011 heat accumulation distribution using only MODIS data was finally demonstrated in the current paper. Our study may supply a novel way to calculate AGDD in heat-related study concerning crop growth monitoring, agricultural climatic regionalization, and agro-meteorological disaster detection at the regional scale. PMID:23365013

  8. Seasonal prediction of lightning activity in North Western Venezuela: Large-scale versus local drivers

    NASA Astrophysics Data System (ADS)

    Muñoz, Á. G.; Díaz-Lobatón, J.; Chourio, X.; Stock, M. J.

    2016-05-01

    The Lake Maracaibo Basin in North Western Venezuela has the highest annual lightning rate of any place in the world (~ 200 fl km- 2 yr- 1), whose electrical discharges occasionally impact human and animal lives (e.g., cattle) and frequently affect economic activities like oil and natural gas exploitation. Lightning activity is so common in this region that it has a proper name: Catatumbo Lightning (plural). Although short-term lightning forecasts are now common in different parts of the world, to the best of the authors' knowledge, seasonal prediction of lightning activity is still non-existent. This research discusses the relative role of both large-scale and local climate drivers as modulators of lightning activity in the region, and presents a formal predictability study at seasonal scale. Analysis of the Catatumbo Lightning Regional Mode, defined in terms of the second Empirical Orthogonal Function of monthly Lightning Imaging Sensor (LIS-TRMM) and Optical Transient Detector (OTD) satellite data for North Western South America, permits the identification of potential predictors at seasonal scale via a Canonical Correlation Analysis. Lightning activity in North Western Venezuela responds to well defined sea-surface temperature patterns (e.g., El Niño-Southern Oscillation, Atlantic Meridional Mode) and changes in the low-level meridional wind field that are associated with the Inter-Tropical Convergence Zone migrations, the Caribbean Low Level Jet and tropical cyclone activity, but it is also linked to local drivers like convection triggered by the topographic configuration and the effect of the Maracaibo Basin Nocturnal Low Level Jet. The analysis indicates that at seasonal scale the relative contribution of the large-scale drivers is more important than the local (basin-wide) ones, due to the synoptic control imposed by the former. Furthermore, meridional CAPE transport at 925 mb is identified as the best potential predictor for lightning activity in the Lake

  9. Storm activity in North Atlantic and precipitation anomalies in European region during winter seasons

    NASA Astrophysics Data System (ADS)

    Vyazilova, N. A.; Vyazilova, A. E.

    2009-09-01

    The purpose of this paper is to show the storm activity influence on the formation of wet and dry zone in North Atlantic and European region during winter seasons 1994/95, 2006/07 and 2007/08 years with positive mode of NAO, 1995/96, 2000/01 and 2005/06 years with negative mode of NAO. The study of storm activity includes the analyses of cyclonic intensity and cyclone track number. Analyses of cyclonic intensity based on calculation cyclone centers number (CCN) and sum of cyclone centers MSLP anomalies (CCMA). This analyses based on automated cyclone tracking algorithm and the 6-hourly MSLP from the NCEP/NCAR reanalyses 2 from 1979 to 2009. Precipitation anomalies were calculated from CMAP archive. Analyses had included the calculation of cyclone track number in all region [30°N-80°N, 50°W-70°E]and selected latitude zone for long cyclones (with lifetime more 2 day) and short cyclones (with lifetime less 2 day). The study had shown the special features of CCN and CCMA patterns in region for long and short cyclones. The study shows, that every winter season short cyclone track number twice as much long cyclone track number. However, the contribution of long cyclones in main determines the CCMA in region. Study had shown that winter seasons with positive NAO mode Nord Europe were outstanding by strong positive precipitation anomalies and strong cyclonic intensity, and during winter seasons with negative NAO mode in this region were observed negative precipitation anomalies and weak cyclonic activity. Standartizide anomalies of integral CCMA for selected latitude zone [55°N-80°N, 50°W-70°E] had shown the intensification of cyclonic activity over North Atlantic and North European region in last years.

  10. Seasonal brain acetylcholinesterase activity in three species of shorebirds overwintering in Texas

    USGS Publications Warehouse

    Mitchell, C.A.; White, D.H.

    1982-01-01

    There was no seasonal variation in average brain AChE activity for the 3 species of wild birds collected between October and February. Further work needs to be done, however, covering an even broader time frame which includes the reproductive cycle. It appears that some birds feeding at the mouth of an agricultural drain, at some distance from the nearest pesticide applications, were affected by AChE inhibitors.

  11. Different Apparent Gas Exchange Coefficients for CO2 and CH4: Comparing a Brown-Water and a Clear-Water Lake in the Boreal Zone during the Whole Growing Season.

    PubMed

    Rantakari, Miitta; Heiskanen, Jouni; Mammarella, Ivan; Tulonen, Tiina; Linnaluoma, Jessica; Kankaala, Paula; Ojala, Anne

    2015-10-01

    The air-water exchange of carbon dioxide (CO2) and methane (CH4) is a central process during attempts to establish carbon budgets for lakes and landscapes containing lakes. Lake-atmosphere diffusive gas exchange is dependent on the concentration gradient between air and surface water and also on the gas transfer velocity, often described with the gas transfer coefficient k. We used the floating-chamber method in connection with surface water gas concentration measurements to estimate the gas transfer velocity of CO2 (kCO2) and CH4 (kCH4) weekly throughout the entire growing season in two contrasting boreal lakes, a humic oligotrophic lake and a clear-water productive lake, in order to investigate the earlier observed differences between kCO2 and kCH4. We found that the seasonally averaged gas transfer velocity of CH4 was the same for both lakes. When the lakes were sources of CO2, the gas transfer velocity of CO2 was also similar between the two study lakes. The gas transfer velocity of CH4 was constantly higher than that of CO2 in both lakes, a result also found in other studies but for reasons not yet fully understood. We found no differences between the lakes, demonstrating that the difference between kCO2 and kCH4 is not dependent on season or the characteristics of the lake.

  12. Different Apparent Gas Exchange Coefficients for CO2 and CH4: Comparing a Brown-Water and a Clear-Water Lake in the Boreal Zone during the Whole Growing Season.

    PubMed

    Rantakari, Miitta; Heiskanen, Jouni; Mammarella, Ivan; Tulonen, Tiina; Linnaluoma, Jessica; Kankaala, Paula; Ojala, Anne

    2015-10-01

    The air-water exchange of carbon dioxide (CO2) and methane (CH4) is a central process during attempts to establish carbon budgets for lakes and landscapes containing lakes. Lake-atmosphere diffusive gas exchange is dependent on the concentration gradient between air and surface water and also on the gas transfer velocity, often described with the gas transfer coefficient k. We used the floating-chamber method in connection with surface water gas concentration measurements to estimate the gas transfer velocity of CO2 (kCO2) and CH4 (kCH4) weekly throughout the entire growing season in two contrasting boreal lakes, a humic oligotrophic lake and a clear-water productive lake, in order to investigate the earlier observed differences between kCO2 and kCH4. We found that the seasonally averaged gas transfer velocity of CH4 was the same for both lakes. When the lakes were sources of CO2, the gas transfer velocity of CO2 was also similar between the two study lakes. The gas transfer velocity of CH4 was constantly higher than that of CO2 in both lakes, a result also found in other studies but for reasons not yet fully understood. We found no differences between the lakes, demonstrating that the difference between kCO2 and kCH4 is not dependent on season or the characteristics of the lake. PMID:26359720

  13. Seasonal influenza activity in Hong Kong and its association with meteorological variations.

    PubMed

    Chan, Paul K S; Mok, H Y; Lee, T C; Chu, Ida M T; Lam, Wai-Yip; Sung, Joseph J Y

    2009-10-01

    Influenza seasons appear consistently in the temperate regions, but are more variable in tropical/subtropical regions. The determinant for such variation remains poorly understood. This study documented the activity of influenza over a 10-year period in Hong Kong; examining its association with changes in temperature and relative humidity. The two types of influenza exhibited different correlations with meteorological variations. Influenza A showed two seasonal peaks occurring respectively in winter/spring and summer months in most years. Influenza B showed a clear winter/spring peak, but its activity during summer months was more variable. Cold and humid conditions were associated with a higher activity of both influenza A and B. In contrast, hot and humid conditions were associated with a higher activity of influenza A, but were associated with only a moderate, less consistent increase in the activity of influenza B. A trend of increase in the magnitude of summer peaks of influenza A, but not influenza B, was observed. A hypothetical 2 degrees C rise in temperature would decrease the proportion of favorable days for influenza A in December-April from 78% to 57%, but an increase from 58% to 71% in May-November; with a similar effect (from 83% to 62%) for influenza B during December-April, but a modest change (from 17% to 18%) during May-November. The presence of two seasonal peaks of influenza annually emphasizes the need to evaluate the duration of protective immunity offered by vaccination. Further study on the effects of climate change and global warming on the activity of influenza is warranted.

  14. Monitoring seasonal bat activity on a coastal barrier island in Maryland, USA.

    PubMed

    Johnson, Joshua B; Gates, J Edward; Zegre, Nicolas P

    2011-02-01

    Research on effects of wind turbines on bats has increased dramatically in recent years because of significant numbers of bats killed by rotating wind turbine blades. Whereas most research has focused on the Midwest and inland portions of eastern North America, bat activity and migration on the Atlantic Coast has largely been unexamined. We used three long-term acoustic monitoring stations to determine seasonal bat activity patterns on the Assateague Island National Seashore, a barrier island off the coast of Maryland, from 2005 to 2006. We recorded five species, including eastern red bats (Lasiurus borealis), big brown bats (Eptesicus fuscus), hoary bats (Lasiurus cinereus), tri-colored bats (Perimyotis subflavus), and silver-haired bats (Lasionycteris noctivagans). Seasonal bat activity (number of bat passes recorded) followed a cosine function and gradually increased beginning in April, peaked in August, and declined gradually until cessation in December. Based on autoregressive models, inter-night bat activity was autocorrelated for lags of seven nights or fewer but varied among acoustic monitoring stations. Higher nightly temperatures and lower wind speeds positively affected bat activity. When autoregressive model predictions were fitted to the observed nightly bat pass totals, model residuals>2 standard deviations from the mean existed only during migration periods, indicating that periodic increases in bat activity could not be accounted for by seasonal trends and weather variables alone. Rather, the additional bat passes were attributable to migrating bats. We conclude that bats, specifically eastern red, hoary, and silver-haired bats, use this barrier island during migration and that this phenomenon may have implications for the development of near and offshore wind energy.

  15. Monitoring seasonal bat activity on a coastal barrier island in Maryland, USA.

    PubMed

    Johnson, Joshua B; Gates, J Edward; Zegre, Nicolas P

    2011-02-01

    Research on effects of wind turbines on bats has increased dramatically in recent years because of significant numbers of bats killed by rotating wind turbine blades. Whereas most research has focused on the Midwest and inland portions of eastern North America, bat activity and migration on the Atlantic Coast has largely been unexamined. We used three long-term acoustic monitoring stations to determine seasonal bat activity patterns on the Assateague Island National Seashore, a barrier island off the coast of Maryland, from 2005 to 2006. We recorded five species, including eastern red bats (Lasiurus borealis), big brown bats (Eptesicus fuscus), hoary bats (Lasiurus cinereus), tri-colored bats (Perimyotis subflavus), and silver-haired bats (Lasionycteris noctivagans). Seasonal bat activity (number of bat passes recorded) followed a cosine function and gradually increased beginning in April, peaked in August, and declined gradually until cessation in December. Based on autoregressive models, inter-night bat activity was autocorrelated for lags of seven nights or fewer but varied among acoustic monitoring stations. Higher nightly temperatures and lower wind speeds positively affected bat activity. When autoregressive model predictions were fitted to the observed nightly bat pass totals, model residuals>2 standard deviations from the mean existed only during migration periods, indicating that periodic increases in bat activity could not be accounted for by seasonal trends and weather variables alone. Rather, the additional bat passes were attributable to migrating bats. We conclude that bats, specifically eastern red, hoary, and silver-haired bats, use this barrier island during migration and that this phenomenon may have implications for the development of near and offshore wind energy. PMID:20364316

  16. Seasonal and Daily Activity Patterns of Mosquito (Diptera: Culicidae) Vectors of Pathogens in Northeastern Italy.

    PubMed

    Montarsi, Fabrizio; Mazzon, Luca; Cazzin, Stefania; Ciocchetta, Silvia; Capelli, Gioia

    2015-01-01

    The seasonal and daily activity of mosquito vectors of pathogens affecting animals and humans were studied in northeastern Italy at a site within the Po River Delta Park. A CDC-CO2 trap and a gravid trap were operated at 2-h intervals for 24 h every 15 d from May to October 2010. Overall, 5,788 mosquitoes comprising six species were collected, namely Culex pipiens L. (75.1% of total), Aedes caspius (Pallas) (15.2%), Aedes vexans (Meigen) (6.9%), Anopheles maculipennis s.l. Meigen (2.6%), Culiseta annulata (Schrank) (0.2%), and Culex modestus Ficalbi (<0.1%). The relative abundance of these species increased from May until the beginning of July and then decreased, disappearing at the beginning of October. The diel host-seeking patterns and oviposition site-seeking patterns were species specific and were differentially affected by the ecological variables recorded at the day and hour of mosquito collection or two weeks before collection. Knowledge of the seasonal and daily host-seeking patterns of mosquitoes highlights the time periods of the day and the seasons of potential exposure for animals and humans to mosquito-borne pathogens, therefore delineating the best time for the application of preventive measures. Furthermore, knowledge of the oviposition site-seeking activity of the mosquitoes optimizes the capture of gravid females, thereby enhancing the likelihood of detecting pathogens.

  17. Intake, digestibility, nitrogen efficiency, and animal performance of growing and finishing beef cattle fed warm-season legume (Stylosanthes capitata plus Stylosanthes macrocephala) silage replacing corn silage.

    PubMed

    Souza, W F; Pereira, O G; Ribeiro, K G; Santos, S A; Valadares Filho, S C

    2014-09-01

    It was hypothesized that Stylosanthes cv. Campo Grande (ES) silage could be used as the single source of dietary forage for beef cattle and that performance on ES would be similar to corn silage (CS) at a 50:50 forage:concentrate. The objectives of this study were to evaluate intake, total and partial digestibility of nutrients, ruminal pH, ruminal ammonia, and productive performance in growing beef cattle fed diets with varying proportions of ES silage replacing CS. Treatments consisted of diets with ratios of 0:100, 25:75, 50:50, 75:25, and 100:0% ES:CS. Two experiments were conducted simultaneously. In the first experiment, 10 crossbred Holstein-Zebu bulls with an average initial weight of 272 ± 86 kg were used. The bulls were rumen and abomasums fistulated. An experimental design of two 5 × 5 Latin squares (Exp. 1) was used. The second experiment used 40 Nellore bulls with an average BW of 386 ± 30 kg in a completely randomized design (Exp. 2). Results showed a linear increase in CP intake (P < 0.05) in response to increased dietary ES. An increase in the proportion of ES in the diet had a negative linear effect on TDN. Apparent ruminal digestibility of CP increased linearly, and apparent intestinal digestibility of nonfibrous carbohydrates increased with the addition of ES to the diet (P < 0.05). Intestinal digestibility of DM exhibited a quadratic response (P < 0.05). Nitrogen balance, excretion of urinary urea, and plasma urea nitrogen did not respond to the inclusion of ES in the diet (P > 0.05). There was also no effect (P > 0.05) of ES inclusion on animal performance. Ruminal pH was not affected by an increased proportion of ES in the diet (P > 0.05), but ruminal pH was affected (P < 0.05) by the time of collection, for which a cubic model fit the data. There was an interaction (P < 0.05) between treatment and collection time for ruminal ammonia nitrogen concentration. It can be concluded that ES silage can be used as a source of roughage in the diet

  18. Mosquito repellent activity of essential oils of aromatic plants growing in Argentina.

    PubMed

    Gillij, Y G; Gleiser, R M; Zygadlo, J A

    2008-05-01

    Mosquitoes are important vectors of diseases and nuisance pests. Repellents minimize contact with mosquitoes. Repellents based on essential oils (EO) are being developed as an alternative to DEET (N,N-diethyl-m-methylbenzamide), an effective compound that has disadvantages including toxic reactions, and damage to plastic and synthetic fabric. This work evaluated the repellency against Aedes aegypti of EO from aromatic plants that grow in Argentina: Acantholippia seriphioides, Achyrocline satureioides, Aloysia citriodora, Anemia tomentosa, Baccharis spartioides, Chenopodium ambrosioides, Eucalyptus saligna, Hyptis mutabilis, Minthostachys mollis, Rosmarinus officinalis, Tagetes minuta and Tagetes pusilla. Most EO were effective. Variations depending on geographic origin of the plant were detected. At a 90% EO concentration, A. satureoides and T. pusilla were the least repellent. At concentrations of 12.5% B. spartioides, R. officinalis and A. citriodora showed the longest repellency times. Comparisons of the principal components of each EO suggest that limonene and camphor were the main components responsible for the repellent effects.

  19. Mosquito repellent activity of essential oils of aromatic plants growing in Argentina.

    PubMed

    Gillij, Y G; Gleiser, R M; Zygadlo, J A

    2008-05-01

    Mosquitoes are important vectors of diseases and nuisance pests. Repellents minimize contact with mosquitoes. Repellents based on essential oils (EO) are being developed as an alternative to DEET (N,N-diethyl-m-methylbenzamide), an effective compound that has disadvantages including toxic reactions, and damage to plastic and synthetic fabric. This work evaluated the repellency against Aedes aegypti of EO from aromatic plants that grow in Argentina: Acantholippia seriphioides, Achyrocline satureioides, Aloysia citriodora, Anemia tomentosa, Baccharis spartioides, Chenopodium ambrosioides, Eucalyptus saligna, Hyptis mutabilis, Minthostachys mollis, Rosmarinus officinalis, Tagetes minuta and Tagetes pusilla. Most EO were effective. Variations depending on geographic origin of the plant were detected. At a 90% EO concentration, A. satureoides and T. pusilla were the least repellent. At concentrations of 12.5% B. spartioides, R. officinalis and A. citriodora showed the longest repellency times. Comparisons of the principal components of each EO suggest that limonene and camphor were the main components responsible for the repellent effects. PMID:17583499

  20. Emergency department syndromic surveillance providing early warning of seasonal respiratory activity in England.

    PubMed

    Hughes, H E; Morbey, R; Hughes, T C; Locker, T E; Pebody, R; Green, H K; Ellis, J; Smith, G E; Elliot, A J

    2016-04-01

    Seasonal respiratory infections place an increased burden on health services annually. We used a sentinel emergency department syndromic surveillance system to understand the factors driving respiratory attendances at emergency departments (EDs) in England. Trends in different respiratory indicators were observed to peak at different points during winter, with further variation observed in the distribution of attendances by age. Multiple linear regression analysis revealed acute respiratory infection and bronchitis/bronchiolitis ED attendances in patients aged 1-4 years were particularly sensitive indicators for increasing respiratory syncytial virus activity. Using near real-time surveillance of respiratory ED attendances may provide early warning of increased winter pressures in EDs, particularly driven by seasonal pathogens. This surveillance may provide additional intelligence about different categories of attendance, highlighting pressures in particular age groups, thereby aiding planning and preparation to respond to acute changes in EDs, and thus the health service in general.

  1. [Seasonal peculiarities of the ground squirrel (Spermophilus undulatus) and Wistar rats circadian activity].

    PubMed

    Semenova, T P; Spiridonova, L A; Zakharova, N M

    2014-09-01

    The seasonal peculiarities of the circadian activity of hibernator, Yakutian long tail ground squirrels (S. undulatus) (n = 35) and non hibernator, Wistar rats (n = 35), were studied. The locomotor activity was registered in each subject individually during 5-17 days by means of "Animex" in the different periods of annual cycle. It was shown that ground squirrels were animals with daily type of activity. On the contrary, the Wistar rats demonstrated nocturne type of locomotors activity. The active period in rats was longer than in ground squirrels. It included not only at night, but morning time in spring, and daytime--in summer. The circadian differences between hibernators and non-hibernators were kept during all annual cycle at night time, but in daytime--only in spring and summer time.

  2. Seasonal Short-Lived Radium Activity in the Venice Lagoon: The Role of Residence Time

    NASA Astrophysics Data System (ADS)

    Rapaglia, J.; Ferrarin, C.; Zaggia, L.; Umgiesser, G.; Zuppi, G.; Manfe', G.

    2008-12-01

    Radium is considered to be an excellent tracer of submarine groundwater discharge (SGD) and, therefore, has been used in many studies of this process in the past decade. Comprehensive surveys of excess 223,224Ra activity were completed in the surface waters of the Venice Lagoon over 6 seasons in order to quantify seasonal variation of SGD into the lagoon. The mass balance of radium found that SGD was 5-26 times greater than total river discharge (35.5 m3 s-1), and that total SGD could differ by almost an order of magnitude pending season. Several possible parameters, which may cause the seasonal variation, were tested. These included precipitation events, average tidal elevation, average tidal excursion, wind speed and direction, yet none provided a satisfactory explanation for the difference. Residence time based on a hydrodynamic model, however, was very strongly correlated with the observed variation. When the average residence time in the lagoon was low (5 days) the SGD was calculated to be 930 m3 s-1 and when the average residence time was high (9 days) the SGD was quantified as 160 m3 s-1. Radioactive decay is already accounted for in the mass balance model and therefore this correlation must be explained by another process. The Venice Lagoon is characterized by low residence time during periods of spring tides and bora or northerly winds, both of which create exceptionally strong currents in the Venice Lagoon. The currents as well as the large tidal excursion which occurs at spring tides drive a recirculation of seawater through the surface sediments, which greatly increases short-lived Ra activity in the surface waters. This evidence suggests, therefore, that short-lived Ra mass balance studies, which are based on a single survey, may under or overestimate the mean annual SGD pending the hydrodynamics of the investigated location.

  3. Melatonin concentrations in the two jugular veins, and relationship with the seasonal reproductive activity in goats.

    PubMed

    Zarazaga, L A; Celi, I; Guzmán, J L; Malpaux, B

    2010-07-15

    The authors investigated whether melatonin concentrations vary between the two jugular veins and whether absolute (nocturnal) or relative (nocturnal/diurnal ratio) plasma melatonin concentrations are associated with seasonal reproductive activity measured by oestrus or ovulatory activity in Payoya goats. Thirty-two adult Payoya goats were penned under natural photoperiod. Oestrus activity was tested daily using aproned males-twice a week plasma was sampled for progesterone. Melatonin plasma concentrations were studied at each equinox and solstice of the year in jugular samples taken simultaneously by venipuncture. Nocturnal and diurnal plasma melatonin concentrations from each jugular vein were assessed in 3 and 2 plasma samples per goat, respectively, taken at hourly intervals in each period. No differences in melatonin concentrations between the two veins were observed, but there was a significant interaction (P < 0.001) between jugular vein and animal in nocturnal melatonin concentrations. There was no effect of sampling period on melatonin concentrations and the coefficient of correlation between sampling periods was very high. The analyses performed indicated that neither absolute nor relative melatonin concentrations were related with the dates of onset or end of ovulatory/oestrus activity. Therefore, we concluded that in goats (1) melatonin concentrations are highly variable between jugular veins in the same individual but not in the general population, (2) melatonin concentrations are highly repeatable for each individual, and (3) absolute and relative amplitudes of melatonin concentrations are not linked to the seasonal breeding activity in Mediterranean goats. PMID:20451998

  4. Antifungal activity of the essential oil from Calendula officinalis L. (asteraceae) growing in Brazil.

    PubMed

    Gazim, Zilda Cristiane; Rezende, Claudia Moraes; Fraga, Sandra Regina; Svidzinski, Terezinha Inez Estivaleti; Cortez, Diógenes Aparicio Garcia

    2008-01-01

    This study tested in vitro activity of the essential oil from flowers of Calendula officinalis using disk-diffusion techniques. The antifungal assay results showed for the first time that the essential oil has good potential antifungal activity: it was effective against all 23 clinical fungi strains tested. PMID:24031180

  5. Growing Good Kids: 28 Activities To Enhance Self-Awareness, Compassion, and Leadership.

    ERIC Educational Resources Information Center

    Delisle, Deb; Delisle, Jim

    This book offers teachers of grades 3-8 creative and fun activities that build students' skills in problem solving, decision making, cooperative learning, divergent thinking, and communication. The book offers 28 diverse and original enrichment activities that teach personal values such as responsibility, compassion, leadership, and respect for…

  6. Antifungal activity of the essential oil from Calendula officinalis L. (asteraceae) growing in Brazil

    PubMed Central

    Gazim, Zilda Cristiane; Rezende, Claudia Moraes; Fraga, Sandra Regina; Svidzinski, Terezinha Inez Estivaleti; Cortez, Diógenes Aparicio Garcia

    2008-01-01

    This study tested in vitro activity of the essential oil from flowers of Calendula officinalis using disk-diffusion techniques. The antifungal assay results showed for the first time that the essential oil has good potential antifungal activity: it was effective against all 23 clinical fungi strains tested. PMID:24031180

  7. The Green Pages Environmental Education Activities K-12: Gardens for Young Growing Lives.

    ERIC Educational Resources Information Center

    Larson, Jan

    1997-01-01

    Describes several gardening activities that can be kept simple or used as a foundation for more in-depth projects. Activities include setting up an indoor garden spot, making compost which helps students understand the terms "decompose" and "compost", watching plants drink in which students measure water movement in plants, making herb gardens,…

  8. Deficient repair of potentially lethal damage in actively growing ataxia telangiectasia cells

    SciTech Connect

    Utsumi, H.; Sasaki, M.S.

    1984-02-01

    The repair of potentially lethal damage after X rays was studied in exponentially growing normal and ataxia telangiectasia (A-T) strains of human fibroblasts. X-ray killing of all normal strains from six healthy persons was enhanced when cells were treated with hypertonic phosphate-buffered saline immediately after irradiation. This treatment is not toxic to unirradiated cells and demonstrates that ordinarily these cells repair potentially lethal damage. The potentially lethal damage in normal cells is repaired within 1 hr. In contrast, all A-T strains from four A-T patients were completely deficient in their ability to repair potentially lethal damage. Treatment with a hypertonic solution after X irradiation is known to increase the frequency of chromosomal aberrations and to enhance cell killing, as though hypertonicity had induced the A-T state in normal cells. These results support the inference that the increased radiosensitivity of A-T cells can be attributed to some defect in the repair of DNA damage rather than abnormal DNA synthesis following irradiation.

  9. Variety and Harvesting Season Effects on Antioxidant Activity and Vitamins Content of Citrus sinensis Macfad.

    PubMed

    Cardeñosa, Vanessa; Barreira, João C M; Barros, Lillian; Arenas-Arenas, Francisco J; Moreno-Rojas, José M; Ferreira, Isabel C F R

    2015-05-07

    Five sweet orange (Citrus sinensis Osbeck) varieties cultivated in Huelva (Spain) and picked at two seasons during two consecutive years, were characterized for their antioxidant activity (free radicals scavenging activity, reducing power and lipid peroxidation inhibition) and vitamin content (vitamin E and vitamin C). The effects induced by sweet orange variety and stage of maturity were comprehensively compared by applying 2-way ANOVA and linear discriminant analysis. The results indicated higher differences in antioxidant activity and vitamin contents in response to the effect of the harvesting season, when compared to the effect of sweet orange variety. Nevertheless, the results observed in 2012 showed less marked differences among the assayed sweet orange varieties. Either way, it might be concluded that oranges sampled in January show the highest antioxidant activity and vitamin contents. Furthermore, concerning the properties evaluated in this work, all sweet orange varieties represent good alternatives, except for Rhode Summer, which would not be the preferable choice as a target to enhance sweet orange overall characteristics.

  10. Seasonal variations in Be-7 activity in the sediments of Cape Lookout Bight, North Carolina

    NASA Technical Reports Server (NTRS)

    Canuel, E. A.; Martens, C. S.; Benninger, L. K.

    1990-01-01

    The short-term sediment-accumulation rates in the interior of the Cape Lookout Bight (North Caroline) were determined using data on Be-7 activity distribution in the surface of sediments of the bight. Lack of a significant bioturbation in this lagoon made it possible to interpret variations in depth-integrated activity profiles of Be-7 as short-term accumulation events. The accumulation rates calculated from Be-7 activity profiles indicate that the delivery of particulate matter to the sediments of Cape Lookout Bight is not constant throughout an annual cycle, with the highest monthly accumulation rates being associated with north/northeast storm activity. Inputs were found to be highest during the late winter/early spring season, when the storm frequency is greatest.

  11. Antibacterial and antifungal activities of different parts of Tribulus terrestris L. growing in Iraq.

    PubMed

    Al-Bayati, Firas A; Al-Mola, Hassan F

    2008-02-01

    Antimicrobial activity of organic and aqueous extracts from fruits, leaves and roots of Tribulus terrestris L., an Iraqi medicinal plant used as urinary anti-infective in folk medicine, was examined against 11 species of pathogenic and non-pathogenic microorganisms: Staphylococcus aureus, Bacillus subtilis, Bacillus cereus, Corynebacterium diphtheriae, Escherichia coli, Proteus vulgaris, Serratia marcescens, Salmonella typhimurium, Klebsiella pneumoniae, Pseudomonas aeruginosa and Candida albicans using microdilution method in 96 multiwell microtiter plates. All the extracts from the different parts of the plant showed antimicrobial activity against most tested microorganisms. The most active extract against both Gram-negative and Gram-positive bacteria was ethanol extract from the fruits with a minimal inhibitory concentration (MIC) value of 0.15 mg/ml against B. subtilis, B. cereus, P. vulgaris and C. diphtheriae. In addition, the same extract from the same plant part demonstrated the strongest antifungal activity against C. albicans with an MIC value of 0.15 mg/ml.

  12. Interaction Activities in the Foreign Classroom, or How to Grow a Tulip-Rose

    ERIC Educational Resources Information Center

    Paulston, Christina Bratt; Selekman, Howard R.

    1976-01-01

    A report is made on the use of foreign language for spontaneous communication in an elementary language class. Four correction-free, peer communicative/interaction activities are outlined according to procedures, objectives, and evaluations. (Author/RM)

  13. Seasonal variation in daily activity patterns of free-ranging European ground squirrels (Spermophilus citellus).

    PubMed

    Everts, Lammina G; Strijkstra, Arjen M; Hut, Roelof A; Hoffmann, Ilse E; Millesi, Eva

    2004-01-01

    Daily aboveground activity of European ground squirrels (Spermophilus citellus) in their natural habitat was recorded with a visual scanning procedure during the active seasons of 1992 and 1993. Activity patterns were analyzed with respect to time of year and to the animal's reproductive state. Aboveground activity started on average 3.9 h (SD 0.6 h, n = 37 days) after civil twilight at dawn and ended on average 3.2 h (SD 0.9 h, n = 37 days) before civil twilight at dusk. Between onset and offset of activity, 54% was spent aboveground, of which 73% was spent foraging. Activity patterns were influenced by photoperiod, rainfall, and by reproductive state. During mating, reproductively active males started activity earlier than females and reproductively inactive males. For females, time spent foraging was high during lactation. The midpoint of daily activity was at 12:16 h (SD 0.37 h, n = 37 days). Activity patterns of European ground squirrels thus appear robustly positioned in the middle of the photoperiod. PMID:15129824

  14. Visualizing in situ translational activity for identifying and sorting slow-growing archaeal−bacterial consortia

    PubMed Central

    Hatzenpichler, Roland; Connon, Stephanie A.; Goudeau, Danielle; Malmstrom, Rex R.; Woyke, Tanja; Orphan, Victoria J.

    2016-01-01

    To understand the biogeochemical roles of microorganisms in the environment, it is important to determine when and under which conditions they are metabolically active. Bioorthogonal noncanonical amino acid tagging (BONCAT) can reveal active cells by tracking the incorporation of synthetic amino acids into newly synthesized proteins. The phylogenetic identity of translationally active cells can be determined by combining BONCAT with rRNA-targeted fluorescence in situ hybridization (BONCAT-FISH). In theory, BONCAT-labeled cells could be isolated with fluorescence-activated cell sorting (BONCAT-FACS) for subsequent genetic analyses. Here, in the first application, to our knowledge, of BONCAT-FISH and BONCAT-FACS within an environmental context, we probe the translational activity of microbial consortia catalyzing the anaerobic oxidation of methane (AOM), a dominant sink of methane in the ocean. These consortia, which typically are composed of anaerobic methane-oxidizing archaea (ANME) and sulfate-reducing bacteria, have been difficult to study due to their slow in situ growth rates, and fundamental questions remain about their ecology and diversity of interactions occurring between ANME and associated partners. Our activity-correlated analyses of >16,400 microbial aggregates provide the first evidence, to our knowledge, that AOM consortia affiliated with all five major ANME clades are concurrently active under controlled conditions. Surprisingly, sorting of individual BONCAT-labeled consortia followed by whole-genome amplification and 16S rRNA gene sequencing revealed previously unrecognized interactions of ANME with members of the poorly understood phylum Verrucomicrobia. This finding, together with our observation that ANME-associated Verrucomicrobia are found in a variety of geographically distinct methane seep environments, suggests a broader range of symbiotic relationships within AOM consortia than previously thought. PMID:27357680

  15. Visualizing in situ translational activity for identifying and sorting slow-growing archaeal-bacterial consortia.

    PubMed

    Hatzenpichler, Roland; Connon, Stephanie A; Goudeau, Danielle; Malmstrom, Rex R; Woyke, Tanja; Orphan, Victoria J

    2016-07-12

    To understand the biogeochemical roles of microorganisms in the environment, it is important to determine when and under which conditions they are metabolically active. Bioorthogonal noncanonical amino acid tagging (BONCAT) can reveal active cells by tracking the incorporation of synthetic amino acids into newly synthesized proteins. The phylogenetic identity of translationally active cells can be determined by combining BONCAT with rRNA-targeted fluorescence in situ hybridization (BONCAT-FISH). In theory, BONCAT-labeled cells could be isolated with fluorescence-activated cell sorting (BONCAT-FACS) for subsequent genetic analyses. Here, in the first application, to our knowledge, of BONCAT-FISH and BONCAT-FACS within an environmental context, we probe the translational activity of microbial consortia catalyzing the anaerobic oxidation of methane (AOM), a dominant sink of methane in the ocean. These consortia, which typically are composed of anaerobic methane-oxidizing archaea (ANME) and sulfate-reducing bacteria, have been difficult to study due to their slow in situ growth rates, and fundamental questions remain about their ecology and diversity of interactions occurring between ANME and associated partners. Our activity-correlated analyses of >16,400 microbial aggregates provide the first evidence, to our knowledge, that AOM consortia affiliated with all five major ANME clades are concurrently active under controlled conditions. Surprisingly, sorting of individual BONCAT-labeled consortia followed by whole-genome amplification and 16S rRNA gene sequencing revealed previously unrecognized interactions of ANME with members of the poorly understood phylum Verrucomicrobia This finding, together with our observation that ANME-associated Verrucomicrobia are found in a variety of geographically distinct methane seep environments, suggests a broader range of symbiotic relationships within AOM consortia than previously thought. PMID:27357680

  16. Alcohol consumption inhibits bone growth and development in young actively growing rats.

    PubMed

    Sampson, H W; Perks, N; Champney, T H; DeFee, B

    1996-11-01

    Adolescence is an age of widespread alcohol abuse, but the effect of alcohol consumption on bone formation has not been studied in the young population. This study addresses the effect of alcohol on the early phases of bone growth and development in an animal model. Four-week-old, female Sprague-Dawley rats were divided into three groups. Alcohol-treated animals were fed a modified Lieber-DeCarli diet ad libitum containing 35% ethanol-derived calories, whereas the pair-fed animals (weight-matched to ethanol rats) received an isocaloric liquid diet in which maltose-dextrin substituted calories supplied by ethanol. Chow animals were fed a standard rat chow ad libitum. Proximal tibiae (primarily cancellous bone) and femora (primarily cortical bone) were removed for analysis after 2, 4, 6, or 8 weeks on the diets. Serum was collected for analysis of calcium levels, osteocalcin, corticosterone, growth hormone, parathyroid hormone, and 25-hydroxyvitamin D. The most rapid weight gain occurred between 6 and 8 weeks of age, it was significantly delayed in alcohol and pair-fed animals. Almost all morphological parameters of bone were lower in the alcohol groups. No significant difference in serum calcium levels, osteocalcin, or growth hormone levels were found, and small difference in calciotropic hormone levels was found between groups. The results indicated that chronic alcohol consumption during the age of bone development reduces bone density and peak bone mass in both cortical and cancellous bone. The mechanism whereby this effect occurs is not fully understood, but, our results suggest that the negative impact of alcohol on growing bone is not due to the secondary effects of altered bone mineral regulating hormones.

  17. Dichloromethane dehalogenase with improved catalytic activity isolated from a fast-growing dichloromethane-utilizing bacterium

    SciTech Connect

    Scholtz, R.; Egli, C.; Cook, A.M.; Leisinger, T. ); Wackett, L.P. )

    1988-12-01

    A methylotrophic bacterium, denoted strain DM11, was isolated from groundwater and shown to utilize dichloromethane or dibromomethane as the sole carbon and energy source. The new isolate grew at the high rate of 0.22 h{sup {minus}1} compared with 11 previously characterized dichloromethane-utilizing bacteria ({mu}{sub max}, 0.08 h{sup {minus}1}). The dichloromethane dehalogenase from strain DM11 (group B enzyme) was purified by anion-exchange chromatography. It was shown to be substantially different from the set of dichloromethane dehalogenases from the 11 slow-growing strains (group A enzymes) that had previously been demonstrated to be identical. The V{sub max} for the group B enzyme was 97 mkat/kg of protein, some 5.6-fold higher than that of the group A enzymes. The group A dehalogenases showed hyperbolic saturation with the cosubstrate glutathione, whereas the group B enzyme showed positive cooperativity in glutathione binding. Only 1 of 15 amino acids occupied common positions at the N termini, and amino acid contents were substantially different in group A and group B dehalogenases. Immunological assays demonstrated weak cross-reactivity between the two enzymes. Despite the observed structural and kinetic differences, there is potentially evolutionary relatedness between group A and group B enzymes, as indicated by (i) hybridization of DM11 DNA with a gene probe of the group A enzyme, (ii) a common requirement for glutathione in catalysis, and (iii) similar subunit molecular weights of about 34,000.

  18. Variability of Physical Activity Patterns by Type of Day and Season in 8-10-Year-Old Boys

    ERIC Educational Resources Information Center

    Rowlands, Ann V.; Hughes, Dylan R.

    2006-01-01

    The aims of this study were to: (a) compare physical activity across two seasons and, within those seasons, across school and vacation time, and (b) compare the proportion of children meeting the activity thresholds recommended by Tudor-Locke et al. (2004) at each time point. Thirty-six boys, between the ages of 8 and 10 years (M age = 8.8 years,…

  19. Inequity outside the Classroom: Growing Class Differences in Participation in Extracurricular Activities

    ERIC Educational Resources Information Center

    Snellman, Kaisa; Silva, Jennifer M.; Putnam, Robert D.

    2015-01-01

    In this article, the authors report on research that shows that extracurricular activities help cultivate the skills, connections, and knowledge that prepare children for lifelong success. They add, however, that low-income students are increasingly being excluded from participating. Struggling with budget cuts and deficits, many school districts…

  20. Antibacterial and antifungal activities of different parts of Tribulus terrestris L. growing in Iraq

    PubMed Central

    Al-Bayati, Firas A.; Al-Mola, Hassan F.

    2008-01-01

    Antimicrobial activity of organic and aqueous extracts from fruits, leaves and roots of Tribulus terrestris L., an Iraqi medicinal plant used as urinary anti-infective in folk medicine, was examined against 11 species of pathogenic and non-pathogenic microorganisms: Staphylococcus aureus, Bacillus subtilis, Bacillus cereus, Corynebacterium diphtheriae, Escherichia coli, Proteus vulgaris, Serratia marcescens, Salmonella typhimurium, Klebsiella pneumoniae, Pseudomonas aeruginosa and Candida albicans using microdilution method in 96 multiwell microtiter plates. All the extracts from the different parts of the plant showed antimicrobial activity against most tested microorganisms. The most active extract against both Gram-negative and Gram-positive bacteria was ethanol extract from the fruits with a minimal inhibitory concentration (MIC) value of 0.15 mg/ml against B. subtilis, B. cereus, P. vulgaris and C. diphtheriae. In addition, the same extract from the same plant part demonstrated the strongest antifungal activity against C. albicans with an MIC value of 0.15 mg/ml. PMID:18257138

  1. Growing into Greatness: A Study of a Local History Group of Active-Retired Learners

    ERIC Educational Resources Information Center

    Corrigan, Trudy; Byrne, Brid; Harris, Phyllis; Lalor, Maureen; O'Connor, Maura; O'Reilly, Kathleen; Quinn, Frank; Forde, Kathleen

    2005-01-01

    Research in Canada on the learning needs of older people looked at such issues as how to cope with changes in society, the need to make a contribution and the need to be influential. The White Paper on Adult Education "Learning for Life" notes that strategies for active ageing stress the critical importance of access to learning as a key tool in…

  2. Antimycoplasmic activity and seasonal variation of essential oil of Eugenia hiemalis Cambess. (Myrtaceae).

    PubMed

    Zatelli, Gabriele Andressa; Zimath, Priscila; Tenfen, Adrielli; Mendes de Cordova, Caio Maurício; Scharf, Dilamara Riva; Simionatto, Edésio Luiz; Alberton, Michele Debiasi; Falkenberg, Miriam

    2016-09-01

    The purpose of this work was to study the chemical composition and antimycoplasmic and anticholinesterase activities of the essential oil of Eugenia hiemalis leaves collected throughout the year. A total of 42 compounds were identified by CG, and are present in almost every seasons. Sesquiterpenes were dominant (86.01-91.48%), and non-functionalised sesquiterpenes comprised the major fraction, which increased in the summer; monoterpenes were not identified. The major components were spathulenol (5.36-16.06%), δ-cadinene (7.50-15.93%), bicyclogermacrene (5.70-14.24%) and β-caryophyllene (4.80-9.43%). The highest oil yield was obtained in summer and autumn. Essential oils presented activity against three evaluated Mycoplasma strains, but no activity was observed in the anticholinesterase assay.

  3. Seasonal, interannual, and long-term variabilities in biomass burning activity over South Asia.

    PubMed

    Bhardwaj, P; Naja, M; Kumar, R; Chandola, H C

    2016-03-01

    The seasonal, interannual, and long-term variations in biomass burning activity and related emissions are not well studied over South Asia. In this regard, active fire location retrievals from the Moderate Resolution Imaging Spectroradiometer (MODIS), the retrievals of aerosol optical depth (AOD) from MODIS Terra, and tropospheric column NO2 from Ozone Monitoring Instrument (OMI) are used to understand the effects of biomass burning on the tropospheric pollution loadings over South Asia during 2003-2013. Biomass burning emission estimates from Global Fire Emission Database (GFED) and Global Fire Assimilation System (GFAS) are also used to quantify uncertainties and regional discrepancies in the emissions of carbon monoxide (CO), nitrogen oxide (NOx), and black carbon (BC) due to biomass burning in South Asia. In the Asian continent, the frequency of fire activity is highest over Southeast Asia, followed by South Asia and East Asia. The biomass burning activity in South Asia shows a distinct seasonal cycle that peaks during February-May with some differences among four (north, central, northeast, and south) regions in India. The annual biomass burning activity in north, central, and south regions shows an increasing tendency, particularly after 2008, while a decrease is seen in northeast region during 2003-2013. The increase in fire counts over the north and central regions contributes 24 % of the net enhancement in fire counts over South Asia. MODIS AOD and OMI tropospheric column NO2 retrievals are classified into high and low fire activity periods and show that biomass burning leads to significant enhancement in tropospheric pollution loading over both the cropland and forest regions. The enhancement is much higher (110-176 %) over the forest region compared to the cropland (34-62 %) region. Further efforts are required to understand the implications of biomass burning on the regional air quality and climate of South Asia.

  4. Latitudinal variation in seasonal activity and mortality in ratsnakes (Elaphe obsoleta).

    PubMed

    Sperry, Jinelle H; Blouin-Demers, Gabriel; Carfagno, Gerardo L F; Weatherhead, Patrick J

    2010-06-01

    The ecology of ectotherms should be particularly affected by latitude because so much of their biology is temperature dependent. Current latitudinal patterns should also be informative about how ectotherms will have to modify their behavior in response to climate change. We used data from a total of 175 adult black ratsnakes (Elaphe obsoleta) radio-tracked in Ontario, Illinois, and Texas, a latitudinal distance of >1500 km, to test predictions about how seasonal patterns of activity and mortality should vary with latitude. Despite pronounced differences in temperatures among study locations, and despite ratsnakes in Texas not hibernating and switching from diurnal to nocturnal activity in the summer, seasonal patterns of snake activity were remarkably similar during the months that snakes in all populations were active. Rather than being a function of temperature, activity may be driven by the timing of reproduction, which appears similar among populations. Contrary to the prediction that mortality should be highest in the most active population, overall mortality did not follow a clinal pattern. Winter mortality did increase with latitude, however, consistent with temperature limiting the northern distribution of ratsnakes. This result was opposite that found in the only previous study of latitudinal variation in winter mortality in reptiles, which may be a consequence of whether or not the animals exhibit true hibernation. Collectively, these results suggest that, at least in the northern part of their range, ratsnakes should be able to adjust easily to, and may benefit from, a warmer climate, although climate-based changes to the snakes' prey or habitat, for example, could alter that prediction. PMID:20583726

  5. Seasonal, interannual, and long-term variabilities in biomass burning activity over South Asia.

    PubMed

    Bhardwaj, P; Naja, M; Kumar, R; Chandola, H C

    2016-03-01

    The seasonal, interannual, and long-term variations in biomass burning activity and related emissions are not well studied over South Asia. In this regard, active fire location retrievals from the Moderate Resolution Imaging Spectroradiometer (MODIS), the retrievals of aerosol optical depth (AOD) from MODIS Terra, and tropospheric column NO2 from Ozone Monitoring Instrument (OMI) are used to understand the effects of biomass burning on the tropospheric pollution loadings over South Asia during 2003-2013. Biomass burning emission estimates from Global Fire Emission Database (GFED) and Global Fire Assimilation System (GFAS) are also used to quantify uncertainties and regional discrepancies in the emissions of carbon monoxide (CO), nitrogen oxide (NOx), and black carbon (BC) due to biomass burning in South Asia. In the Asian continent, the frequency of fire activity is highest over Southeast Asia, followed by South Asia and East Asia. The biomass burning activity in South Asia shows a distinct seasonal cycle that peaks during February-May with some differences among four (north, central, northeast, and south) regions in India. The annual biomass burning activity in north, central, and south regions shows an increasing tendency, particularly after 2008, while a decrease is seen in northeast region during 2003-2013. The increase in fire counts over the north and central regions contributes 24 % of the net enhancement in fire counts over South Asia. MODIS AOD and OMI tropospheric column NO2 retrievals are classified into high and low fire activity periods and show that biomass burning leads to significant enhancement in tropospheric pollution loading over both the cropland and forest regions. The enhancement is much higher (110-176 %) over the forest region compared to the cropland (34-62 %) region. Further efforts are required to understand the implications of biomass burning on the regional air quality and climate of South Asia. PMID:26503008

  6. Profile of some plasma enzyme activities in growing dwarf and landrace kids.

    PubMed

    Mbassa, G K; Poulsen, J S

    1991-10-01

    Plasma alanine aminotransferase, aspartate aminotransferase, creatine kinase and alkaline phosphatase activities were studied in clinically healthy Danish landrace and dwarf kids in seven herds from birth to 12 months of age. The purpose was to evaluate the influence of age, breed and herd on reference values. The mean enzyme levels +/- standard deviation (s) in neonatal dwarf kids were 0.09 +/- 0.04, 1.23 +/- 0.24, 2.79 +/- 1.50 and 18.3 +/- 11.0 mu kat/l respectively. The respective values in landrace kids were 0.13 +/- 0.06, 1.06 +/- 0.22, 2.44 +/- 1.60 and 37.6 +/- 23.6 mu kat/l. In 8-12 months old dwarf kids they were 0.30 +/- 0.11, 1.49 +/- 0.13, 3.28 +/- 0.44 and 11.1 +/- 2.4 mu kat/l respectively and 0.23 +/- 0.05, 1.12 +/- 0.34, 3.68 +/- 1.63 and 14.1 +/- 8.40 mu kat/l respectively in landrace kids of the same age. The 5th to 95th percentile intervals of the enzyme activities were within mean +/- 2s for most age groups in both breeds except alkaline phosphatase. The means and medians were close to each other for the values of alanine aminotransferase, aspartate aminotransferase and creatine kinase but not for alkaline phosphatase. Alanine aminotransferase, aspartate aminotransferase and creatine kinase levels were low at birth and increased with age, whereas for alkaline phosphatase it was vice versa. Significant differences were observed in mean enzyme activities between kids of different ages (within breeds), breeds (in same age kids) and herds (within same breed and age kids). Sex variations (within the breeds) were not observed. It was concluded that plasma enzyme activities are dependent on age, breed and environment.

  7. Growing older with health and vitality: a nexus of physical activity, exercise and nutrition.

    PubMed

    Witard, Oliver C; McGlory, Chris; Hamilton, D Lee; Phillips, Stuart M

    2016-06-01

    The preservation of skeletal muscle mass and strength with advancing age are, we propose, critical aspects of ageing with health and vitality. Physical inactivity and poor nutrition are known to accelerate the gradual age-related decline in muscle mass and strength-sarcopenia-however, both are subject to modification. The main purpose of this review is to present the latest, evidence-based recommendations for physical activity and exercise, as well as diet for older adults that would help in preserving muscle mass and strength. We take the position that future physical activity/exercise guidelines need to make specific reference to resistance exercise and highlight the benefits of higher-intensity aerobic exercise training, alongside advocating older adults perform aerobic-based physical activity and household tasks (e.g., carrying groceries). In terms of dietary recommendations, greater emphasis should be placed on optimal rather than minimum protein intakes for older adults. Indeed, guidelines that endorse a daily protein intake of 1.2-1.5 g/kg BM/day, which are levels 50-90 % greater than the current protein Recommendation Dietary Allowance (0.8 g/kg BM/day), are likely to help preserve muscle mass and strength and are safe for healthy older adults. Being cognisant of factors (e.g., reduced appetite) that may preclude older adults from increasing their total daily protein intake, we echo the viewpoint of other active researchers in advocating that protein recommendations for older adults be based on a per meal approach in order to maximize muscle protein synthesis (MPS). On this basis, assuming three meals are consumed daily, a protein dose of 0.4-0.5 g/kg BM should be contained in each meal. We are beginning to understand ways in which to increase the utilization of ingested protein for the stimulation of MPS, namely by increasing the proportion of leucine contained in a given dose of protein, co-ingesting other nutrients (e.g., carbohydrate and fat or

  8. [SCREENING OF WILD SPREAD AND CULTIVATED OF BUXUS SPECIES GROWING IN GEORGIA ON THE CONTENT OF ALKALOIDS AND BIOLOGICAL ACTIVITY].

    PubMed

    Vachnadze, N; Mchedlidze, Q; Novikova, J; Suladze, T; Vachnadze, V

    2016-07-01

    Georgian flora is represented by about 4150 plant species. Many important alkaloid-containing plant species and among of them are species Buxus L. of genus in Adjara. The aims of the research were: sequential screening of the plants for the consistence of alkaloids; Study of anatomical characteristics of Buxus colchica Pojark. and revealing of specific pharmacological activity of steroidal alkaloids. The objects of research were B. colchica, B. balearika and B. sempervirens, growing in Adjara (Georgia), collected in active phase of flowering of the plants. There were revealed 370 species of alkaloid containing plants. Sum of alkaloids and crude aqueous extract have spasmolitic and antihistaminic activity. Experimental anatomical research of diagnostic characteristics of the bines showed the existence of monocyclic transient system with fiber like tracheids, dorsoventral mesophyll of the leaves; the structure for the upper part of epidermis is linear and the lower part is curved, type of stomata is paracitic. PMID:27661282

  9. Community shifts of actively growing lake bacteria after N-acetyl-glucosamine addition: improving the BrdU-FACS method

    PubMed Central

    Tada, Yuya; Grossart, Hans-Peter

    2014-01-01

    In aquatic environments, community dynamics of bacteria, especially actively growing bacteria (AGB), are tightly linked with dissolved organic matter (DOM) quantity and quality. We analyzed the community dynamics of DNA-synthesizing and accordingly AGB by linking an improved bromodeoxyuridine immunocytochemistry approach with fluorescence-activated cell sorting (BrdU-FACS). FACS-sorted cells of even oligotrophic ecosystems in winter were characterized by 16S rRNA gene analysis. In incubation experiments, we examined community shifts of AGB in response to the addition of N-acetyl-glucosamine (NAG), one of the most abundant aminosugars in aquatic systems. Our improved BrdU-FACS analysis revealed that AGB winter communities of oligotrophic Lake Stechlin (northeastern Germany) substantially differ from those of total bacteria and consist of Alpha-, Beta-, Gamma-, Deltaproteobacteria, Actinobacteria, Candidatus OP10 and Chloroflexi. AGB populations with different BrdU-fluorescence intensities and cell sizes represented different phylotypes suggesting that single-cell growth potential varies at the taxon level. NAG incubation experiments demonstrated that a variety of widespread taxa related to Alpha-, Beta-, Gammaproteobacteria, Bacteroidetes, Actinobacteria, Firmicutes, Planctomycetes, Spirochaetes, Verrucomicrobia and Chloroflexi actively grow in the presence of NAG. The BrdU-FACS approach enables detailed phylogenetic studies of AGB and, thus, to identify those phylotypes which are potential key players in aquatic DOM cycling. PMID:23985742

  10. Dpp Signaling Activity Requires Pentagone to Scale with Tissue Size in the Growing Drosophila Wing Imaginal Disc

    PubMed Central

    Pyrowolakis, George; Bergmann, Sven; Affolter, Markus

    2011-01-01

    The wing of the fruit fly, Drosophila melanogaster, with its simple, two-dimensional structure, is a model organ well suited for a systems biology approach. The wing arises from an epithelial sac referred to as the wing imaginal disc, which undergoes a phase of massive growth and concomitant patterning during larval stages. The Decapentaplegic (Dpp) morphogen plays a central role in wing formation with its ability to co-coordinately regulate patterning and growth. Here, we asked whether the Dpp signaling activity scales, i.e. expands proportionally, with the growing wing imaginal disc. Using new methods for spatial and temporal quantification of Dpp activity and its scaling properties, we found that the Dpp response scales with the size of the growing tissue. Notably, scaling is not perfect at all positions in the field and the scaling of target gene domains is ensured specifically where they define vein positions. We also found that the target gene domains are not defined at constant concentration thresholds of the downstream Dpp activity gradients P-Mad and Brinker. Most interestingly, Pentagone, an important secreted feedback regulator of the pathway, plays a central role in scaling and acts as an expander of the Dpp gradient during disc growth. PMID:22039350

  11. Dpp signaling activity requires Pentagone to scale with tissue size in the growing Drosophila wing imaginal disc.

    PubMed

    Hamaratoglu, Fisun; de Lachapelle, Aitana Morton; Pyrowolakis, George; Bergmann, Sven; Affolter, Markus

    2011-10-01

    The wing of the fruit fly, Drosophila melanogaster, with its simple, two-dimensional structure, is a model organ well suited for a systems biology approach. The wing arises from an epithelial sac referred to as the wing imaginal disc, which undergoes a phase of massive growth and concomitant patterning during larval stages. The Decapentaplegic (Dpp) morphogen plays a central role in wing formation with its ability to co-coordinately regulate patterning and growth. Here, we asked whether the Dpp signaling activity scales, i.e. expands proportionally, with the growing wing imaginal disc. Using new methods for spatial and temporal quantification of Dpp activity and its scaling properties, we found that the Dpp response scales with the size of the growing tissue. Notably, scaling is not perfect at all positions in the field and the scaling of target gene domains is ensured specifically where they define vein positions. We also found that the target gene domains are not defined at constant concentration thresholds of the downstream Dpp activity gradients P-Mad and Brinker. Most interestingly, Pentagone, an important secreted feedback regulator of the pathway, plays a central role in scaling and acts as an expander of the Dpp gradient during disc growth.

  12. Responses to Global Warming Over the Eastern and Central Tibetan Plateau as Reflected in Day-time and Night-time Temperatures, Extreme Temperature Events, and Growing Season Length During 1961-2003

    NASA Astrophysics Data System (ADS)

    Yin, Z.; Liu, X.; Shao, X.

    2006-12-01

    This study examines the trends and variation patterns in daily maximum (day-time) and minimum (night-time) temperatures (hereafter referred to as Tm and Tn), extreme events, and growing season lengths over the eastern and central Tibetan Plateau (TP), in comparison with the results from other regions. Data during the period 1961-2003 from 66 weather stations over the eastern and central TP with elevations above 2000 m are used in this study, after going through rigorous quality assessment/quality control procedures. Statistically significant warming trends are identified in various measures of the temperature regime, especially in night- time temperatures, extreme warm/cold events, and diurnal temperature range (DTR). We find that the trends in Tn and Tm display distinct spatial patterns in the study region. The warming trends in winter night-time temperatures are among the highest when compared with studies conducted in other regions. Our results also confirm the asymmetric pattern of greater warming trends in minimum or night-time temperatures as compared to the day-time temperatures, which reduces the DTR in the region. Based on the time-varying percentiles of Tn and Tm, prominent warming trends are found in Tn during cold season months across the relative temperature scale of both warm and cold events. The warming in night-time temperatures causes the number of frost days to decrease significantly and the number of warm days to increase. The mean length of growing season has increased by approximately 17 days during the 43-year study period for the region. Most of the record-setting months for cold events are found in the earlier part of the study period, while that of the warm events have occurred mostly in the later half, especially since the 1990s. The changes in the temperature regime in this region may have brought regional-specific impacts on the ecosystems. It is found that grain production in Qinghai Province, located in the northeastern part of the

  13. Effect of age and season on the thyroid hormone activity of Mizoram strain female mithun (Bos frontalis)

    PubMed Central

    Lalsangpuii; Ali, M. Ayub; Devi, L. Inaotombi; Behera, Parthasarathi; Ralte, Lalsanglura

    2015-01-01

    Aim: The aim of the present study was to generate baseline data on the normal values of the thyroidhormone (TH) activity as well as their correlation with age and season. Materials and Methods: Blood samples (10 ml) were collected from jugular vein of 30 female mithun’s of three different age groups viz. Calves (6 months to 1 year), heifer (1-3 years) and adult (above 3 years) during the three season’s viz. Monsoon, winter and spring of a year. The serum was analyzed for thyroid stimulating hormone (TSH), triiodothyronine (T3), and thyroxine (T4) activity. Result: The result showed a significantly (p<0.05) a higher T3 level in heifers followed by adults and calves and higher T4 level in adults followed by heifers and calves in all the seasons. The TSH level was higher in heifers in all the seasons. The winter season recorded higher level of T3, T4, and TSH as compared to the other seasons of a year. Conclusion: The TSH and T3 level were the highest for aheifer, whereas T4 level was the highest for adults inall the season. Furthermore, the higher level of TH was observed in winter season. The increased level of the TH during the winter season signifies their calorigenic effect. Similarly in heifers, the increased T3 concentrations show its importance in reproductive physiology and its association with ovarian activity. This indicates that age and season have aprofound effect on TH activity of Mizoram strain female mithun. PMID:27047046

  14. Serum copper and ceruloplasmin activity at the early growing stage in foals.

    PubMed Central

    Okumura, M; Asano, M; Tagami, M; Tsukiyama, K; Fujinaga, T

    1998-01-01

    Serum concentrations of copper (Cu), zinc (Zn), manganese (Mn), calcium (Ca) and inorganic phosphorus (P), as well as antigenic ceruloplasmin (Cp) and oxidase activity as a functional index for copper metabolism, were measured in 10 foals (5 males and 5 females) and their dams. Samples were harvested from the foals within 1 wk after birth and monthly from 1 to 17 mo of age. Samples were collected from their dams in the perinatal period (monthly from 2 mo before delivery to 5 mo postpartum). Serum oxidase activity, antigenic Cp and Cu in foals were extremely low at 1 wk. Serum Cp had the lowest value of 17.0 +/- 8.0 (mean +/- SD) mg/dL within the 1st wk, then increased rapidly up to 43.7 +/- 5.8 mg/dL at 1 mo, and maintained this level until the 17th mo. Serum Zn in foals had the highest value of 73.2 +/- 13.1 micrograms/dL within 1 wk, then decreased to 38.3 +/- 5.9 micrograms/dL by 17 mo. Serum Mn, Ca and P in mares were almost stable and within established reference ranges for our laboratory in the perinatal period, and these values in foals were also in the normal range. Even on appropriate feeding, serum Cu, Cp and oxidase activity were quite low a few weeks after birth, while a higher proportion of Cp-binding copper was found in the foals. This might be caused by the limited synthesis of ceruloplasmin in this period. These data suggest that newborn foals are in a critical situation of marginal copper status in the early stage of growth. PMID:9553711

  15. Plant Growth Promotion Activity of Keratinolytic Fungi Growing on a Recalcitrant Waste Known as "Hair Waste".

    PubMed

    Cavello, Ivana A; Crespo, Juan M; García, Sabrina S; Zapiola, José M; Luna, María F; Cavalitto, Sebastián F

    2015-01-01

    Purpureocillium lilacinum (Thom) Samsom is one of the most studied fungi in the control of plant parasitic nematodes. However, there is not specific information on its ability to inhibit some pathogenic bacteria, fungi, or yeast. This work reports the production of several antifungal hydrolytic enzymes by a strain of P. lilacinum when it is grown in a medium containing hair waste. The growth of several plant-pathogenic fungi, Alternaria alternata, Aspergillus niger, and Fusarium culmorum, was considerably affected by the presence of P. lilacinum's supernatant. Besides antifungal activity, P. lilacinum demonstrates the capability to produce indoleacetic acid and ammonia during time cultivation on hair waste medium. Plant growth-promoting activity by cell-free supernatant was evidenced through the increase of the percentage of tomato seed germination from 71 to 85% after 48 hours. A 21-day plant growth assay using tomato plants indicates that crude supernatant promotes the growth of the plants similar to a reference fertilizer (p > 0.05). These results suggest that both strain and the supernatant may have potential to be considered as a potent biocontrol agent with multiple plant growth-promoting properties. To our knowledge, this is the first report on the antifungal, IAA production and tomato growth enhancing compounds produced by P. lilacinum LPSC #876.

  16. Essential Oil Composition, Antioxidant, Cytotoxic and Antiviral Activities of Teucrium pseudochamaepitys Growing Spontaneously in Tunisia.

    PubMed

    Hammami, Saoussen; Jmii, Habib; El Mokni, Ridha; Khmiri, Abdelbaki; Faidi, Khaled; Dhaouadi, Hatem; El Aouni, Mohamed Hédi; Aouni, Mahjoub; Joshi, Rajesh K

    2015-01-01

    The chemical composition, antioxidant, cytotoxic and antiviral activities of the essential oil obtained by hydrodistillation from the aerial parts of Teucrium pseudochamaepitys (Lamiaceae) collected from Zaghouan province of Tunisia are reported. The essential oil was analyzed by gas chromatography equipped with a flame ionization detector (GC-FID) and gas chromatography coupled with mass spectrometry (GC/MS). Thirty-one compounds were identified representing 88.6% of the total essential oil. Hexadecanoic acid was found to be the most abundant component (26.1%) followed by caryophyllene oxide (6.3%), myristicin (4.9%) and α-cubebene (3.9%). The antioxidant capacity of the oil was measured on the basis of the scavenging activity to the stable 2,2-diphenyl-1-picrylhydrazyl (DPPH). The IC50 value of the oil was evaluated as 0.77 mg·mL(-1). In addition, the essential oil was found to possess moderate cytotoxic effects on the HEp-2 cell line (50% cytotoxic concentration (CC50)=653.6 µg·mL(-1)). The potential antiviral effect was tested against Coxsackievirus B (CV-B), a significant human and mouse pathogen that causes pediatric central nervous system disease, commonly with acute syndromes. The reduction of viral infectivity by the essential oil was measured using a cytopathic (CPE) reduction assay. PMID:26580590

  17. Chemical composition and antimicrobial activity of the essential oils from four Ruta species growing in Algeria.

    PubMed

    Haddouchi, Farah; Chaouche, Tarik Mohammed; Zaouali, Yosr; Ksouri, Riadh; Attou, Amina; Benmansour, Abdelhafid

    2013-11-01

    Antimicrobial properties of plants essential oils have been investigated in order to suggest them as potential tools to overcome the microbial drug resistance and the increasing incidence of food borne diseases problems. The aim of this research is to study the antibacterial and antifungal effects of four traditional plants essential oils, Ruta angustifolia, Ruta chalepensis, Ruta graveolens and Ruta tuberculata, against standard bacterial and fungal strains. The chemical compounds of the oils were examined by GC/MS. Results revealed a powerful antifungal activity against filamentous fungi. Aspergillus fumigatus and Cladosporium herbarum are the most sensitive strains to these oils with MIC values less than 3.5 μg ml(-1) for certain oils, reaching 7.8 μg ml(-1) for other. GC/MS essay exhibited ketones as the most abundant constituent of these oils except for R. tuberculata essential oil which has a completely different composition, monoterpenes alcohols being the most abundant. These compositions explain their potential antifungal activity.

  18. Plant Growth Promotion Activity of Keratinolytic Fungi Growing on a Recalcitrant Waste Known as "Hair Waste".

    PubMed

    Cavello, Ivana A; Crespo, Juan M; García, Sabrina S; Zapiola, José M; Luna, María F; Cavalitto, Sebastián F

    2015-01-01

    Purpureocillium lilacinum (Thom) Samsom is one of the most studied fungi in the control of plant parasitic nematodes. However, there is not specific information on its ability to inhibit some pathogenic bacteria, fungi, or yeast. This work reports the production of several antifungal hydrolytic enzymes by a strain of P. lilacinum when it is grown in a medium containing hair waste. The growth of several plant-pathogenic fungi, Alternaria alternata, Aspergillus niger, and Fusarium culmorum, was considerably affected by the presence of P. lilacinum's supernatant. Besides antifungal activity, P. lilacinum demonstrates the capability to produce indoleacetic acid and ammonia during time cultivation on hair waste medium. Plant growth-promoting activity by cell-free supernatant was evidenced through the increase of the percentage of tomato seed germination from 71 to 85% after 48 hours. A 21-day plant growth assay using tomato plants indicates that crude supernatant promotes the growth of the plants similar to a reference fertilizer (p > 0.05). These results suggest that both strain and the supernatant may have potential to be considered as a potent biocontrol agent with multiple plant growth-promoting properties. To our knowledge, this is the first report on the antifungal, IAA production and tomato growth enhancing compounds produced by P. lilacinum LPSC #876. PMID:26697226

  19. Phenolic composition, physicochemical properties and antioxidant activity of interspecific hybrids of grapes growing in Poland.

    PubMed

    Samoticha, Justyna; Wojdyło, Aneta; Golis, Tomasz

    2017-01-15

    The study evaluated fruit quality parameters and chemical properties (soluble solids, pH, total acidity and total sugars content, phenolic compounds and antioxidant activity (ABTS, FRAP and ORAC methods)) of 30 grape cultivars of white, red and pink grape, as 28 interspecific hybrids and 2 Vitis vinifera L. popularly grown in Poland. Some of them were analyzed for the first time. A total of 49 polyphenolic compounds were identified by LC-PDA-QTOF/MS and quantified by UPLC-PDA-FL, as 26 anthocyanins, 9 flavonols and flavons, 7 phenolic acids, 6 flavan-3-ols, and 1 stilbene. The content of total polyphenols ranged from 1037.0 (Cascade cv.) to 5759.1mg/100gdm (Roesler cv.). However, the content of stilbene represented by trans resveratrol-3-glucoside was only 18.5-70.5mg/100gdm. Red grape cultivars like Roesler, Rothay and Swenson Red were characterized by the highest content of bioactive compounds and antioxidant activity (significantly more than 24, 12 and 53mmol TE/100gdm, by ABTS, FRAP and ORAC, respectively). Average total acidity and soluble solids for white (0.95g of tartaric acid in 100gfm and 17.1°Bx, respectively) and for red and pink (0.93g of tartaric acid in 100gfm and 17.4°Bx, respectively) cultivars were not significantly different (p>0.05). PMID:27542475

  20. Chemical composition and antimicrobial activity of essential oils from Scabiosa arenaria Forssk: growing wild in Tunisia.

    PubMed

    Besbes, Malek; Omri, Amel; Cheraif, Imed; Daami, Mejda; Jannet, Hichem Ben; Mastouri, Maha; Aouni, Mahjoub; Selmi, Boulbaba

    2012-04-01

    The essential oils isolated from three organs, i.e., fruits, stems and leaves, and flowers, of the endemic North African plant Scabiosa arenaria Forssk. were screened for their chemical composition, as well as their possible antibacterial, anticandidal, and antifungal properties. According to the GC-FID and GC/MS analyses, 61 (99.26% of the total oil composition), 79 (98.43%), and 51 compounds (99.9%) were identified in the three oils, respectively. While α-thujone (34.39%), camphor (17.48%), and β-thujone (15.29%) constituted the major compounds of the fruit oil, chrysanthenone (23.43%), together with camphor (12.98%) and α-thujone (10.7%), were the main constituents of the stem and leaf oil. In the case of the flower oil, also chrysanthenone (38.52%), camphor (11.75%), and α-thujone (9.5%) were identified as the major compounds. Furthermore, the isolated oils were tested against 16 Gram-positive and Gram-negative bacteria, four Candida species, and nine phytopathogenic fungal strains. It was found that the oils exhibited interesting antibacterial and anticandidal activities, comparable to those of thymol, which was used as positive control, but no activity against the phytopathogenic fungal strains was observed.

  1. Essential Oil Composition, Antioxidant, Cytotoxic and Antiviral Activities of Teucrium pseudochamaepitys Growing Spontaneously in Tunisia.

    PubMed

    Hammami, Saoussen; Jmii, Habib; El Mokni, Ridha; Khmiri, Abdelbaki; Faidi, Khaled; Dhaouadi, Hatem; El Aouni, Mohamed Hédi; Aouni, Mahjoub; Joshi, Rajesh K

    2015-11-16

    The chemical composition, antioxidant, cytotoxic and antiviral activities of the essential oil obtained by hydrodistillation from the aerial parts of Teucrium pseudochamaepitys (Lamiaceae) collected from Zaghouan province of Tunisia are reported. The essential oil was analyzed by gas chromatography equipped with a flame ionization detector (GC-FID) and gas chromatography coupled with mass spectrometry (GC/MS). Thirty-one compounds were identified representing 88.6% of the total essential oil. Hexadecanoic acid was found to be the most abundant component (26.1%) followed by caryophyllene oxide (6.3%), myristicin (4.9%) and α-cubebene (3.9%). The antioxidant capacity of the oil was measured on the basis of the scavenging activity to the stable 2,2-diphenyl-1-picrylhydrazyl (DPPH). The IC50 value of the oil was evaluated as 0.77 mg·mL(-1). In addition, the essential oil was found to possess moderate cytotoxic effects on the HEp-2 cell line (50% cytotoxic concentration (CC50)=653.6 µg·mL(-1)). The potential antiviral effect was tested against Coxsackievirus B (CV-B), a significant human and mouse pathogen that causes pediatric central nervous system disease, commonly with acute syndromes. The reduction of viral infectivity by the essential oil was measured using a cytopathic (CPE) reduction assay.

  2. Seasonal development of cambial activity in relation to xylem formation in Chinese fir.

    PubMed

    Wu, Hongyang; Xu, Huimin; Li, Hanyin; Wei, Dongmei; Lin, Jinxing; Li, Xiaojuan

    2016-05-20

    The vascular cambium is a lateral meristem which can differentiate into secondary phloem and xylem. The secondary growth of woody plants resulting from vascular cambium activity has been a focus of considerable attention, but the quantitative relationships between cambial activity and secondary xylem formation have been little studied. Our analysis of cytological changes in the cambium of Chinese fir (Cunninghamia lanceolata), revealed a significant positive correlation between vascular cambium cell numbers and cambium zone width through the seasonal cycle. Cambium cell numbers and the cambium cell radial diameter were closely related to xylem formation. Immuno-labeling showed that de-esterified homogalacturonan and (1-4)-β-d-galactan epitopes were highly abundant in cell walls of dormant-stage cambium, whereas high methylesterified homogalacturonan was strongly labeled in the active stage. Raman spectroscopy detected significant changes in the chemical composition of cell walls during the active-dormant stage transition. More pectin and less monolignols occurred in radial cell walls than in tangential walls during the dormant stage, but no significant changes were found in other stages, indicating that pectin accumulation facilitates cell wall expansion, with cambium activity transition. Our quantitative analysis of the relationship between cambial activity and xylem formation, as well as the cell wall modification during the active stage provides useful information about cambial characteristics and xylogenesis.

  3. Isolating weather effects from seasonal activity patterns of a temperate North American Colubrid.

    PubMed

    George, Andrew D; Thompson, Frank R; Faaborg, John

    2015-08-01

    Forecasting the effects of climate change on threatened ecosystems and species will require an understanding of how weather influences processes that drive population dynamics. We have evaluated weather effects on activity patterns of western ratsnakes, a widespread predator of birds and small mammals in eastern North America. From 2010-2013 we radio-tracked 53 ratsnakes in the fragmented region of central Missouri. We relocated each snake 4× per week and used movement frequency as an index of activity. We used generalized linear mixed models within an information-theoretic approach to evaluate temporal and weather variables as potential predictors of snake activity. While snakes were generally sedentary, activity showed a linear response to relative humidity and a quadratic response to air temperature, peaking near 30 °C. Seasonal activity patterns differed between sexes and among years, but snakes were generally least active in mid-summer, regardless of weather. Our findings provide strong evidence that air temperature and relative humidity differentially affect activity patterns of an important predator and are the mechanism explaining increased nest predation rates with warmer temperatures.

  4. [Special effects of a complex probiotic containing cellulolytic bacteria Cellulomonas on actively growing rabbits].

    PubMed

    Ushakova, N A; Laktionov, K S; Kozlova, A A; Ratnikova, I A; Gavrilova, N N

    2013-01-01

    It was shown that the association of probiotic bacteria of the genuses Bacillus and Cellulomonas form biolayers on the surface of beet marc particles. The positive effect of a fodder additive that contained the biolayer on the basis of a phytomatrix on the growth and development of young rabbits was shown. Feeding of animals with a mixed fodder that contained 0.1% preparation resulted in stimulation of digestion of all components of the food. Among other components of the mixed fodder, cellulose was digested most effectively. An increase in the biomass of symbiotic bacteria and enzymatic activity in the blindgut chymus was also observed. The positive nitrogen balance demonstrated an increase in the nitrogen content in animals and a decrease of its losses with excretion. The mechanism of response of the rabbit's organism to introduction of the complex probiotic preparation into the digestive tract is discussed.

  5. Let Nature Be the Teacher: Seasonal Natural History Activities for Parents and Other Educators To Share with Young Children.

    ERIC Educational Resources Information Center

    Gertz, Lucille N.

    This book is designed to provide parents and other adult companions with activities to do with children on outdoor walks. The activities offer adults and children a shared learning experience and have been adapted from the children's education program at Habitat Institute for the Environment (Massachusetts). The activities are arranged seasonally,…

  6. SEASONAL EFFECTS ON COMET NUCLEI EVOLUTION: ACTIVITY, INTERNAL STRUCTURE, AND DUST MANTLE FORMATION

    SciTech Connect

    De Sanctis, M. C.; Capria, M. T.; Lasue, J.

    2010-07-15

    Rotational properties can strongly influence a comet's evolution in terms of activity, dust mantling, and internal structure. In this paper, we investigate the effects of various rotation axis directions on the activity, internal structure, and dust mantling of cometary nuclei. The numerical code developed is able to reproduce different shapes and spin axis inclinations, taking into account both the latitudinal and the longitudinal variations of illumination, using a quasi-three-dimensional approach. The results obtained show that local variations in the dust and gas fluxes can be induced by the different spin axis directions and completely different behaviors of the comet evolution can result in the same cometary shape by using different obliquities of the models. The internal structures of cometary nuclei are also influenced by comet obliquity, as well as dust mantling. Gas and dust production rates show diversities related to the comet seasons.

  7. Influence of season on daytime behavioral activities of donkeys in the Northern Guinea Savanna zone of Nigeria.

    PubMed

    Zakari, Friday Ocheja; Ayo, Joseph Olusegun; Rekwot, Peter Ibrahim; Kawu, Mohammed Umar

    2015-01-01

    The present experiment was performed with the aim of investigating the effect of season on behavioral activities of donkeys during the rainy and harmattan seasons in the Northern Guinea zone of Nigeria. Sixteen apparently healthy donkeys were used as subjects and divided into four groups based on age. During each season, behavioral activities of each donkey were evaluated for three weeks using the focal animal sampling technique. The dry-bulb temperature (DBT), relative humidity (RH), and temperature-humidity index (THI) were obtained three times each day during the experimental period using standard procedures. In the rainy season, the mean DBT (31.65 ± 0.49°C), RH (73.63 ± 1.09%), and THI (84.39 ± 0.71) were significantly (P<0.0001) higher than the corresponding values of 24.00 ± 0.44°C, 36.80 ± 0.92%, and 64.80 ± 0.62 in the harmattan season. During the rainy season, the donkeys spent 60.00 ± 0.77%, 25.40 ± 0.69%, and 2.94 ± 0.21% on grazing, resting, and grooming, respectively. During the harmattan season, the donkeys spent the most time on grazing (76.76 ± 0.43%), less time on resting (11.97 ± 0.38%), and the least time on grooming (0.89 ± 0.05%). In conclusion, season and seasonal variations affect the daytime behavioral activities of donkeys in the zone, and this should be considered in husbandry practices for donkeys. PMID:26858575

  8. Influence of season on daytime behavioral activities of donkeys in the Northern Guinea Savanna zone of Nigeria.

    PubMed

    Zakari, Friday Ocheja; Ayo, Joseph Olusegun; Rekwot, Peter Ibrahim; Kawu, Mohammed Umar

    2015-01-01

    The present experiment was performed with the aim of investigating the effect of season on behavioral activities of donkeys during the rainy and harmattan seasons in the Northern Guinea zone of Nigeria. Sixteen apparently healthy donkeys were used as subjects and divided into four groups based on age. During each season, behavioral activities of each donkey were evaluated for three weeks using the focal animal sampling technique. The dry-bulb temperature (DBT), relative humidity (RH), and temperature-humidity index (THI) were obtained three times each day during the experimental period using standard procedures. In the rainy season, the mean DBT (31.65 ± 0.49°C), RH (73.63 ± 1.09%), and THI (84.39 ± 0.71) were significantly (P<0.0001) higher than the corresponding values of 24.00 ± 0.44°C, 36.80 ± 0.92%, and 64.80 ± 0.62 in the harmattan season. During the rainy season, the donkeys spent 60.00 ± 0.77%, 25.40 ± 0.69%, and 2.94 ± 0.21% on grazing, resting, and grooming, respectively. During the harmattan season, the donkeys spent the most time on grazing (76.76 ± 0.43%), less time on resting (11.97 ± 0.38%), and the least time on grooming (0.89 ± 0.05%). In conclusion, season and seasonal variations affect the daytime behavioral activities of donkeys in the zone, and this should be considered in husbandry practices for donkeys.

  9. Influence of season on daytime behavioral activities of donkeys in the Northern Guinea Savanna zone of Nigeria

    PubMed Central

    ZAKARI, Friday Ocheja; AYO, Joseph Olusegun; REKWOT, Peter Ibrahim; KAWU, Mohammed Umar

    2016-01-01

    ABSTRACT The present experiment was performed with the aim of investigating the effect of season on behavioral activities of donkeys during the rainy and harmattan seasons in the Northern Guinea zone of Nigeria. Sixteen apparently healthy donkeys were used as subjects and divided into four groups based on age. During each season, behavioral activities of each donkey were evaluated for three weeks using the focal animal sampling technique. The dry-bulb temperature (DBT), relative humidity (RH), and temperature-humidity index (THI) were obtained three times each day during the experimental period using standard procedures. In the rainy season, the mean DBT (31.65 ± 0.49°C), RH (73.63 ± 1.09%), and THI (84.39 ± 0.71) were significantly (P<0.0001) higher than the corresponding values of 24.00 ± 0.44°C, 36.80 ± 0.92%, and 64.80 ± 0.62 in the harmattan season. During the rainy season, the donkeys spent 60.00 ± 0.77%, 25.40 ± 0.69%, and 2.94 ± 0.21% on grazing, resting, and grooming, respectively. During the harmattan season, the donkeys spent the most time on grazing (76.76 ± 0.43%), less time on resting (11.97 ± 0.38%), and the least time on grooming (0.89 ± 0.05%). In conclusion, season and seasonal variations affect the daytime behavioral activities of donkeys in the zone, and this should be considered in husbandry practices for donkeys. PMID:26858575

  10. A predictive relationship between early season North Atlantic hurricane activity and the upcoming winter North Atlantic Oscillation

    NASA Astrophysics Data System (ADS)

    Boyd, Jessica; Saunders, Mark

    2016-04-01

    The winter North Atlantic Oscillation (NAO) is linked strongly to European winter climate including windstorms. Predicting the winter NAO is key to making successful seasonal predictions of European winter climate. We observe that in recent decades there are many instances of an inverse relationship between the strength of the North Atlantic hurricane season and the strength of the subsequent European winter windstorm season. Stormy European winter seasons often follow quiet Atlantic hurricane seasons and calm European winters follow active hurricane seasons. We explore the strength and temporal stability of this inverse relationship, consider a facilitating physical mechanism, and briefly discuss the implications of our findings for end users, in particular global reinsurers. We find there is a statistically significant link between North Atlantic hurricane activity and the upcoming winter NAO. The relationship is established by the midway point of the hurricane season in early September. The link is strongest when hurricane activity is in the upper or lower tercile and when summer ENSO (El Niño Southern Oscillation) is neutral. The relationship works well going back 40 years to the mid 1970s. The early winter (October-November-December) NAO is predicted best but since the early 1980s the predictive link extends to the main winter (December-January-February) NAO. The inverse link can be facilitated by a persistence and slow evolution of atmospheric circulation patterns and sea surface temperature anomalies over the North Atlantic between the summer and the winter. This persistence is best when hurricane seasons are more extreme and when summer ENSO is neutral. Our findings offer the potential for predicting the early winter and winter NAO from early September. The implied inverse relationship between US hurricane activity and European windstorm activity may enable more effective offsetting of risks between territories.

  11. Seasonal dynamics of active SAR11 ecotypes in the oligotrophic Northwest Mediterranean Sea

    PubMed Central

    Salter, Ian; Galand, Pierre E; Fagervold, Sonja K; Lebaron, Philippe; Obernosterer, Ingrid; Oliver, Matthew J; Suzuki, Marcelino T; Tricoire, Cyrielle

    2015-01-01

    A seven-year oceanographic time series in NW Mediterranean surface waters was combined with pyrosequencing of ribosomal RNA (16S rRNA) and ribosomal RNA gene copies (16S rDNA) to examine the environmental controls on SAR11 ecotype dynamics and potential activity. SAR11 diversity exhibited pronounced seasonal cycles remarkably similar to total bacterial diversity. The timing of diversity maxima was similar across narrow and broad phylogenetic clades and strongly associated with deep winter mixing. Diversity minima were associated with periods of stratification that were low in nutrients and phytoplankton biomass and characterised by intense phosphate limitation (turnover time<5 h). We propose a conceptual framework in which physical mixing of the water column periodically resets SAR11 communities to a high diversity state and the seasonal evolution of phosphate limitation competitively excludes deeper-dwelling ecotypes to promote low diversity states dominated (>80%) by SAR11 Ia. A partial least squares (PLS) regression model was developed that could reliably predict sequence abundances of SAR11 ecotypes (Q2=0.70) from measured environmental variables, of which mixed layer depth was quantitatively the most important. Comparison of clade-level SAR11 rRNA:rDNA signals with leucine incorporation enabled us to partially validate the use of these ratios as an in-situ activity measure. However, temporal trends in the activity of SAR11 ecotypes and their relationship to environmental variables were unclear. The strong and predictable temporal patterns observed in SAR11 sequence abundance was not linked to metabolic activity of different ecotypes at the phylogenetic and temporal resolution of our study. PMID:25238399

  12. Seasonal changes in the synthesis of the neurosteroid 7alpha-hydroxypregnenolone stimulating locomotor activity in newts.

    PubMed

    Haraguchi, Shogo; Matsunaga, Masahiro; Koyama, Teppei; Do Rego, Jean-Luc; Tsutsui, Kazuyoshi

    2009-04-01

    We recently found that the newt brain actively produces 7alpha-hydroxypregnenolone, a novel amphibian neurosteroid stimulating locomotor activity. It is well known that locomotor activity of male newts increases during the breeding period. To understand the physiological role of 7alpha-hydroxypregnenolone, we investigated seasonal changes in 7alpha-hydroxypregnenolone synthesis in the brain of male newts. Interestingly, 7alpha-hydroxypregnenolone synthesis in the brain showed marked changes during the annual breeding cycle, with a maximal level in the breeding period when locomotor activity of male newts increases. These results suggest that 7alpha-hydroxypregnenolone induces seasonal locomotor changes in male newts.

  13. Sunlight mediated seasonality in canopy structure and photosynthetic activity of Amazonian rainforests

    NASA Astrophysics Data System (ADS)

    Bi, Jian; Knyazikhin, Yuri; Choi, Sungho; Park, Taejin; Barichivich, Jonathan; Ciais, Philippe; Fu, Rong; Ganguly, Sangram; Hall, Forrest; Hilker, Thomas; Huete, Alfredo; Jones, Matthew; Kimball, John; Lyapustin, Alexei I.; Mõttus, Matti; Nemani, Ramakrishna R.; Piao, Shilong; Poulter, Benjamin; Saleska, Scott R.; Saatchi, Sassan S.; Xu, Liang; Zhou, Liming; Myneni, Ranga B.

    2015-06-01

    Resolving the debate surrounding the nature and controls of seasonal variation in the structure and metabolism of Amazonian rainforests is critical to understanding their response to climate change. In situ studies have observed higher photosynthetic and evapotranspiration rates, increased litterfall and leaf flushing during the Sunlight-rich dry season. Satellite data also indicated higher greenness level, a proven surrogate of photosynthetic carbon fixation, and leaf area during the dry season relative to the wet season. Some recent reports suggest that rainforests display no seasonal variations and the previous results were satellite measurement artefacts. Therefore, here we re-examine several years of data from three sensors on two satellites under a range of sun positions and satellite measurement geometries and document robust evidence for a seasonal cycle in structure and greenness of wet equatorial Amazonian rainforests. This seasonal cycle is concordant with independent observations of solar radiation. We attribute alternative conclusions to an incomplete study of the seasonal cycle, i.e. the dry season only, and to prognostications based on a biased radiative transfer model. Consequently, evidence of dry season greening in geometry corrected satellite data was ignored and the absence of evidence for seasonal variation in lidar data due to noisy and saturated signals was misinterpreted as evidence of the absence of changes during the dry season. Our results, grounded in the physics of radiative transfer, buttress previous reports of dry season increases in leaf flushing, litterfall, photosynthesis and evapotranspiration in well-hydrated Amazonian rainforests.

  14. Sunlight Mediated Seasonality in Canopy Structure and Photosynthetic Activity of Amazonian Rainforests

    NASA Astrophysics Data System (ADS)

    Bi, J.; Knyazikhin, Y.; CHOI, S.; Park, T.; Barichivich, J.; Ciais, P.; Fu, R.; Ganguly, S.; Hall, F. G.; Hilker, T.; Huete, A. R.; Jones, M. O.; Kimball, J. S.; Lyapustin, A.; Mottus, M.; Nemani, R. R.; Piao, S.; Poulter, B.; Saleska, S. R.; Saatchi, S. S.; Xu, L.; Zhou, L.; Myneni, R.

    2015-12-01

    Resolving the debate about the nature and controls of seasonal variation in structure and metabolism of Amazonian rainforests is critical to understanding their response to climate change. In situ studies have observed higher photosynthetic and evapotranspiration rates, increased litterfall and leaf flushing during the sunlight-rich dry season. Satellite data also indicated higher greenness level, a proven surrogate of photosynthetic carbon fixation, and leaf area during the dry season relative to the wet season. Some recent reports suggest that rainforests display no seasonal variations and the previous results were satellite measurement artefacts. Therefore, we re-examine here several years of data from three sensors on two satellites under a range of sun positions and satellite measurement geometries and document robust evidence for a seasonal cycle in structure and greenness of wet equatorial Amazonian rainforests. This seasonal cycle is concordant with independent observations of solar radiation. We attribute alternative conclusions to an incomplete study of the seasonal cycle, i.e. the dry season only, and to prognostications based on a biased radiative transfer model. Consequently, evidence of dry season greening in geometry corrected satellite data was ignored and the absence of evidence for seasonal variation in lidar data due to noisy and saturated signals was misinterpreted as evidence of absence of changes during the dry season. Our results, grounded in the physics of radiative transfer, buttress previous reports of dry season increases in leaf flushing, litterfall, photosynthesis and evapotranspiration in well-hydrated Amazonian rainforests.

  15. Seasonal changes in the invertebrate community of granular activated carbon filters and control technologies.

    PubMed

    Wang, Qing; You, Wei; Li, Xiaowei; Yang, Yufeng; Liu, Lijun

    2014-03-15

    Invertebrate colonization of granular activated carbon (GAC) filters in the waterworks is one of the most frequently occurring and least studied biological problems of water processing in China. A survey of invertebrate colonization of GAC filters was carried out weekly from October 2010 to December 2011 at a reservoir water treatment works in South China. Twenty-six kinds of invertebrates were observed. The abundance was as high as 5600ind.m(-3) with a mean of 860ind.m(-3). Large variations in abundance were observed among different seasons and before and after GAC filtration. The dominant organisms were rotifers and copepods. The average invertebrate abundance in the filtrate was 12-18.7 times of that in the pre-filtered water. Results showed that the GAC filters were colonized by invertebrates which may lead to a higher output of organisms in the filtrate than in the pre-filtered water. The invertebrate abundance in the GAC filters was statistically correlated with the water temperature. Seasonal patterns were observed. The invertebrate abundance grew faster in the spring and summer. Copepods were dominant in the summer while rotifers dominated in all other seasons of the year. There was a transition of small invertebrates (rotifers) gradually being substituted by larger invertebrates (copepods) from spring to summer. Control measures such as backwashing with chloric water, drying filter beds and soaking with saliferous water were implemented in the waterworks to reduce invertebrate abundances in the GAC filters. The results showed that soaking with saliferous water (99%, reduction in percent) was best but drying the filter beds (84%) was more economical. Soaking filter beds with 20g/L saliferous water for one day can be implemented in case of emergency. In order to keep invertebrate abundance in the acceptable range, some of these measures should be adopted.

  16. Risks of hormonally active pharmaceuticals to amphibians: a growing concern regarding progestagens.

    PubMed

    Säfholm, Moa; Ribbenstedt, Anton; Fick, Jerker; Berg, Cecilia

    2014-11-19

    Most amphibians breed in water, including the terrestrial species, and may therefore be exposed to water-borne pharmaceuticals during critical phases of the reproductive cycle, i.e. sex differentiation and gamete maturation. The objectives of this paper were to (i) review available literature regarding adverse effects of hormonally active pharmaceuticals on amphibians, with special reference to environmentally relevant exposure levels and (ii) expand the knowledge on toxicity of progestagens in amphibians by determining effects of norethindrone (NET) and progesterone (P) exposure to 0, 1, 10 or 100 ng l(-1) (nominal) on oogenesis in the test species Xenopus tropicalis. Very little information was found on toxicity of environmentally relevant concentrations of pharmaceuticals on amphibians. Research has shown that environmental concentrations (1.8 ng l(-1)) of the pharmaceutical oestrogen ethinylestradiol (EE2) cause developmental reproductive toxicity involving impaired spermatogenesis in frogs. Recently, it was found that the progestagen levonorgestrel (LNG) inhibited oogenesis in frogs by interrupting the formation of vitellogenic oocytes at an environmentally relevant concentration (1.3 ng l(-1)). Results from the present study revealed that 1 ng NET l(-1) and 10 ng P l(-1) caused reduced proportions of vitellogenic oocytes and increased proportions of previtellogenic oocytes compared with the controls, thereby indicating inhibited vitellogenesis. Hence, the available literature shows that the oestrogen EE2 and the progestagens LNG, NET and P impair reproductive functions in amphibians at environmentally relevant exposure concentrations. The progestagens are of particular concern given their prevalence, the range of compounds and that several of them (LNG, NET and P) share the same target (oogenesis) at environmental exposure concentrations, indicating a risk for adverse effects on fertility in exposed wild amphibians.

  17. How faceted liquid droplets grow tails: from surface topology to active motion

    NASA Astrophysics Data System (ADS)

    Sloutskin, Eli

    Among all possible shapes of a volume V, a sphere has the smallest surface area A. Therefore, liquid droplets are spherical, minimizing their interfacial energy γA for a given interfacial tension γ > 0 . This talk will demonstrate that liquid oil (alkane) droplets in water, stabilized by a common surfactant can be temperature-tuned to adopt icosahedral and other faceted shapes, above the bulk melting temperature of the oil. Although emulsions have been studied for centuries no faceted liquid droplets have ever been reported. The formation of an icosahedral shape is attributed to the interplay between γ and the elastic properties of the interfacial monomolecular layer, which crystallizes here 10-15K above bulk melting, leaving the droplet's bulk liquid. The icosahedral symmetry is dictated by twelve five-fold topological defects, forming within the hexagonally-packed interfacial crystalline monolayer. Moreover, we demonstrate that upon further cooling this `interfacial freezing' effect makes γ transiently switch its sign, leading to a spontaneous splitting of droplets and an active growth of their surface area, reminiscent of the classical spontaneous emulsification, yet driven by completely different physics. The observed phenomena allow deeper insights to be gained into the fundamentals of molecular elasticity and open new vitas for a wide range of novel nanotechnological applications, from self-assembly of complex shapes to new delivery strategies in bio-medicine. Acknowledgment is made to the Donors of the American Chemical Society Petroleum Research Fund for support of this research and to the Kahn Foundation for the purchase of equipment.

  18. Antinociceptive activity of extracts and secondary metabolites from wild growing and micropropagated plants of Renealmia alpinia

    PubMed Central

    Gómez-Betancur, Isabel; Cortés, Natalie; Benjumea, Dora; Osorio, Edison; León, Francisco; Cutler, Stephen J.

    2015-01-01

    Ethnopharmacological relevance Renealmia alpinia is native to the American continent and can be found from Mexico to Brazil, and in the Caribbean islands. It is known as “matandrea” in Colombia, and it has been commonly used in traditional medicine to treat painful diseases and ailments. Based on its traditional uses, it is of interest to evaluate the pharmacologic effects of this plant and its secondary metabolites. Materials and methods Methanol and aqueous extracts of wild and micropropagated R. alpinia (leaves) were obtained and chemically compared by High Performance Thin Layer Chromatography (HPTLC). The antinociceptive activity of these extracts was examined using an in vivo assay (Siegmund test). Additionally, the dichloromethane extract of R. alpinia was fractionated and pure compounds were isolated by chromatographic methods. The structure elucidation of isolated compounds was performed by NMR experiments and spectroscopic techniques and comparison with the literature data. Purified compounds were evaluated for their in vitro binding affinity for opioids and cannabinoids receptors. Results The dichloromethane extract of the plant’s aerial part afforded sinostrobin (1), naringenin 7,4′-dimethyl ether (2), 2′,6′-dihydroxy-4′-methoxychalcone (3), 4-methoxy-6-(2-phenylethenyl)-2H-pyran-2-one (4), naringenin 7-methyl ether (5) and 3,5-heptanediol, 1,7-diphenyl (6), which were isolated using chromatographic methods. Their chemical structures were established by physical and spectroscopic techniques. The antinociceptive effects observed in mice by extracts of wild and micropropagated plants were similar. The compounds isolated from R. alpinia do not show affinity to opioid or cannabinoid receptors. Conclusion Aqueous and methanol extracts of R. alpinia provide antinociceptive and analgesic effects in an in vivo model. These results contribute additional insight as to why this plant is traditionally used for pain management. Also, this is the first

  19. Risks of hormonally active pharmaceuticals to amphibians: a growing concern regarding progestagens

    PubMed Central

    Säfholm, Moa; Ribbenstedt, Anton; Fick, Jerker; Berg, Cecilia

    2014-01-01

    Most amphibians breed in water, including the terrestrial species, and may therefore be exposed to water-borne pharmaceuticals during critical phases of the reproductive cycle, i.e. sex differentiation and gamete maturation. The objectives of this paper were to (i) review available literature regarding adverse effects of hormonally active pharmaceuticals on amphibians, with special reference to environmentally relevant exposure levels and (ii) expand the knowledge on toxicity of progestagens in amphibians by determining effects of norethindrone (NET) and progesterone (P) exposure to 0, 1, 10 or 100 ng l−1 (nominal) on oogenesis in the test species Xenopus tropicalis. Very little information was found on toxicity of environmentally relevant concentrations of pharmaceuticals on amphibians. Research has shown that environmental concentrations (1.8 ng l−1) of the pharmaceutical oestrogen ethinylestradiol (EE2) cause developmental reproductive toxicity involving impaired spermatogenesis in frogs. Recently, it was found that the progestagen levonorgestrel (LNG) inhibited oogenesis in frogs by interrupting the formation of vitellogenic oocytes at an environmentally relevant concentration (1.3 ng l−1). Results from the present study revealed that 1 ng NET l−1 and 10 ng P l−1 caused reduced proportions of vitellogenic oocytes and increased proportions of previtellogenic oocytes compared with the controls, thereby indicating inhibited vitellogenesis. Hence, the available literature shows that the oestrogen EE2 and the progestagens LNG, NET and P impair reproductive functions in amphibians at environmentally relevant exposure concentrations. The progestagens are of particular concern given their prevalence, the range of compounds and that several of them (LNG, NET and P) share the same target (oogenesis) at environmental exposure concentrations, indicating a risk for adverse effects on fertility in exposed wild amphibians. PMID:25405966

  20. Antibacterial Activity of Blue Light against Nosocomial Wound Pathogens Growing Planktonically and as Mature Biofilms

    PubMed Central

    Thwaite, Joanne E.; Burt, Rebecca; Laws, Thomas R.; Raguse, Marina; Moeller, Ralf; Webber, Mark A.; Oppenheim, Beryl A.

    2016-01-01

    ABSTRACT The blue wavelengths within the visible light spectrum are intrinisically antimicrobial and can photodynamically inactivate the cells of a wide spectrum of bacteria (Gram positive and negative) and fungi. Furthermore, blue light is equally effective against both drug-sensitive and -resistant members of target species and is less detrimental to mammalian cells than is UV radiation. Blue light is currently used for treating acnes vulgaris and Helicobacter pylori infections; the utility for decontamination and treatment of wound infections is in its infancy. Furthermore, limited studies have been performed on bacterial biofilms, the key growth mode of bacteria involved in clinical infections. Here we report the findings of a multicenter in vitro study performed to assess the antimicrobial activity of 400-nm blue light against bacteria in both planktonic and biofilm growth modes. Blue light was tested against a panel of 34 bacterial isolates (clinical and type strains) comprising Acinetobacter baumannii, Enterobacter cloacae, Stenotrophomonas maltophilia, Pseudomonas aeruginosa, Escherichia coli, Staphylococcus aureus, Enterococcus faecium, Klebsiella pneumoniae, and Elizabethkingia meningoseptica. All planktonic-phase bacteria were susceptible to blue light treatment, with the majority (71%) demonstrating a ≥5-log10 decrease in viability after 15 to 30 min of exposure (54 J/cm2 to 108 J/cm2). Bacterial biofilms were also highly susceptible to blue light, with significant reduction in seeding observed for all isolates at all levels of exposure. These results warrant further investigation of blue light as a novel decontamination strategy for the nosocomial environment, as well as additional wider decontamination applications. IMPORTANCE Blue light shows great promise as a novel decontamination strategy for the nosocomial environment, as well as additional wider decontamination applications (e.g., wound closure during surgery). This warrants further

  1. Seasonal and Solar Cycle Variation of the Martian Ionosphere from Nine Years of MARSIS Active Sounding

    NASA Astrophysics Data System (ADS)

    Morgan, David D.; Withers, Paul; Gurnett, Donald; Nemec, Frantisek

    This past June, we celebrated nine years of continuous operation by MARSIS, the radar sounder on the Mars Express spacecraft, in orbit around Mars since Christmas of 2003. The copious data from this instrument in its Active Ionospheric Sounding mode has been used in numerous scientific endeavors to generate empirical models of the Martian ionosphere. The full ionospheric profiles gleaned from analysis of these data are ideal for this kind of effort. Out of more than 170,000 traces collected, we have selected only about 10%, deemed to be of the best quality, and that can be fit to a Chapman layer function. We now have nine years, or 4-3/4 Mars years, worth of ionospheric traces. In addition to sampling nearly five years of seasonal variation, these nine years of data also represent 80% of a normal solar cycle. Therefore, in this work we shall analyze ionospheric traces with the objective of determining variation of atmospheric and ionospheric parameters such as the neutral atmospheric scale height, ionospheric peak altitude, and ionospheric peak density as they vary with the solar cycle and the change in season.

  2. Seasonal variation of pharmaceutically active compounds in surface (Tagus River) and tap water (Central Spain).

    PubMed

    Valcárcel, Y; Alonso, S González; Rodríguez-Gil, J L; Castaño, A; Montero, J C; Criado-Alvarez, J J; Mirón, I J; Catalá, M

    2013-03-01

    Numerous studies have shown the presence of pharmaceutically active compounds (PhACs) in different environmental compartments, for example, in surface water or wastewater ranging from nanograms per litre to micrograms per litre. Likewise, some recent studies have pointed to seasonal variability, thus indicating that PhAcs concentrations in the aquatic environment may depend on the time of year. This work intended to find out (1) whether Tagus fluvial and drinking water were polluted with different groups of PhACs and (2) if their concentrations differed between winter and summer seasons. From the 58 substances analysed, 41 were found belonging to the main therapeutic groups. Statistical differences were seen for antibacterials, antidepressants, anxiolytics, antiepileptics, and cardiovascular drugs, with higher concentrations being detected in winter than in summer. These results might indicate that the PhACs analysed in this study undergo lower environmental degradation in winter than in summer. In order to confirm these initial results, a continuous monitoring should be performed especially on those PhACs tha