WorldWideScience

Sample records for deposition nutrient cycling

  1. Nutrient cycling strategies.

    NARCIS (Netherlands)

    Breemen, van N.

    1995-01-01

    This paper briefly reviews pathways by which plants can influence the nutrient cycle, and thereby the nutrient supply of themselves and of their competitors. Higher or lower internal nutrient use efficiency positively feeds back into the nutrient cycle, and helps to increase or decrease soil

  2. Inferred effects of cloud deposition on forest floor nutrient cycling and microbial properties along a short elevation gradient

    International Nuclear Information System (INIS)

    Lavoie, M.; Bradley, R.L.

    2003-01-01

    Higher cloud cover significantly decreases forest floor pH, decrease exchangeable cations, modifies mineral-N speciation and increases physiological stress within microbial communities. - Cloud water deposition often increases with elevation, and it is widely accepted that this cloud water increases acid loading to upland forest ecosystems. A study was undertaken in south-eastern Quebec to determine if a 250 m elevation gradient (i.e. 420-665 m), along a uniform sugar-maple stand on the slope of Mount Orford, corresponded to a pH gradient in the forest floor and to predictable changes in soil nutrient availability and microbial properties. Precipitation data from a nearby study, and a photographic survey, provided presumptive evidence that this elevation gradient corresponded to a strong gradient in cloud water deposition. Forest floor temperature did not differ significantly across elevations. Forest floor moisture content was significantly higher, whereas pH and exchangeable Ca and Mg were significantly lower, at the higher elevations. Average seasonal net nitrification rates, determined by long-term laboratory incubations, did not differ significantly across elevations, whereas average seasonal net ammonification rates were significantly higher at higher elevations. Basal respiration rates and microbial biomass did not differ significantly across elevations, but metabolic quotient was significantly higher at higher elevations indicating possible environmental stress on forest floor microbial communities due to cloud water deposition. Anaerobic N mineralisation rates were significantly higher at higher elevations suggesting that N-limited microbial communities frequently exposed to cloud cover can be important short-term sinks for atmospheric N, thereby contributing to increase the active-N fraction of forest floors. We conclude that, where no significant changes in vegetation or temperature occur, elevation gradients can still be used to understand the spatial

  3. Effects of acidic deposition on nutrient uptake, nutrient cycling and growth processes of vegetation in the spruce-fir ecosystem

    Energy Technology Data Exchange (ETDEWEB)

    McLaughlin, S.B.; Garten, C.T.; Wullschleger, S.D. [Oak Ridge National Lab., TN (United States)] [and others

    1996-10-16

    This report summarizes progress in three years of field research designed to evaluate biological and chemical indicators of the current and future health of the Southern Appalachian spruce-fir ecosystem. The emphasis of this research has been on the identification and understanding of mechanisms through which current levels of acidic deposition are impacting ecosystem processes. The identification of these principal mechanisms and key biological indicators of change was designed to improve our capabilities to detect, monitor, and assess the effects of air quality regulations and attendant future air quality changes on ecosystem response. Individual research tasks focused on the following research areas: (1) the significance of foliar uptake of atmospheric sources of nitrogen in relationship to plant utilization of N from available soil reserves; (2) linkages between atmospheric inputs to the soil surface, solution chemistry, and decomposition in the upper organic soil horizons; (3) effects of soil solution chemistry on uptake of cations and aluminum by fine roots; and (4) the effects of varying rates of calcium supply on carbon metabolism of Fraser fir and red spruce, and the relationship between calcium levels in wood cells and integrity of wood formed in bole and branches. Each of the individual tasks was designed to focus upon a mechanism or process that we consider critical to understanding chemical and biological linkages. These linkages will be important determinants in understanding the basis of past and potential future responses of the high elevation Southern Appalachian Forest to acidic deposition and other co-occurring environmental stresses. This report contains (1) background and rationale for the research undertaken in 1992-94; (2) a summary of principal research findings; (3) publications from this research; and (4) characterization of data sets produced by this research which will be the basis of future research, analyses and/or publications.

  4. Impact of simulated atmospheric nitrogen deposition on nutrient cycling and carbon sink via mycorrhizal fungi in two nutrient-poor peatlands

    Science.gov (United States)

    Larmola, Tuula; Kiheri, Heikki; Bubier, Jill L.; van Dijk, Netty; Dise, Nancy; Fritze, Hannu; Hobbie, Erik A.; Juutinen, Sari; Laiho, Raija; Moore, Tim R.; Pennanen, Taina

    2017-04-01

    Peatlands store one third of the global soil carbon (C) pool. Long-term fertilization experiments in nutrient-poor peatlands showed that simulated atmospheric nitrogen (N) deposition does not enhance ecosystem C uptake but reduces C sink potential. Recent studies have shown that a significant proportion of C input to soil in low-fertility forests entered the soil through mycorrhizal fungi, rather than as plant litter. Is atmospheric N deposition diminishing peatland C sink potential due to the suppression of ericoid mycorrhizal fungi? We studied how nutrient addition influences plant biomass allocation and the extent to which plants rely on mycorrhizal N uptake at two of the longest-running nutrient addition experiments on peatlands, Whim Bog, United Kingdom, and Mer Bleue Bog, Canada. We determined the peak growing season aboveground biomass production and coverage of vascular plants using the point intercept method. We also analyzed isotopic δ15N patterns and nutrient contents in leaves of dominant ericoid mycorrhizal shrubs as well as the non-mycorrhizal sedge Eriophorum vaginatum under different nutrient addition treatments. The treatments receive an additional load of 1.6-6.4 N g m-2 y-1 either as ammonium (NH4) nitrate (NO3) or NH4NO3 and with or without phosphorus (P) and potassium (K), alongside unfertilized controls. After 11-16 years of nutrient addition, the vegetation structure had changed remarkably. Ten of the eleven nutrient addition treatments showed an increase of up to 60% in total vascular plant abundance. Only three (NH4Cl, NH4ClPK, NaNO3PK) of the nutrient addition treatments showed a concurrent decrease of down to 50% in the relative proportion of ericoid mycorrhizal shrubs to total vascular plant abundance. The response to nutrient load may be explained by the water table depth, the form of N added and whether N was added with PK. Shrubs were strong competitors at the dry Mer Bleue bog while sedges gained in abundance at the wetter Whim bog

  5. Modelling impacts of atmospheric deposition, nutrient cycling and soil weathering on the sustainability of nine forest ecosystems

    DEFF Research Database (Denmark)

    Salm, C. van der; Vries, W.de; Olsson, M.

    1999-01-01

    To assess the impact of acid deposition on the long-term sustainability of nine oak, pine and spruce stands on sandy to loamy sandy parent material in Sweden, Denmark and The Netherlands, a dynamic soil acidification model (ReSAM) was applied. Two deposition scenarios For the period 1990-2090 were...... is predicted for northern Sweden as deposition levels are below critical loads. Soil chemistry at the recently replanted Swedish sites is dominated by changes in N cycling instead of by deposition. The CL scenario leads, especially after 2010, to a stronger decline in Al concentration compared with the BAU...... scenario, which is mainly caused by a reduction of the acid input. Up to 2010, a considerable acid input to the soil system is maintained as N supply is larger than the consumption of N by the trees. Despite the reduction of the deposition of S and N to critical loads, the readily available cation pools...

  6. Nutrient contributions by benthal sludge deposits.

    Science.gov (United States)

    Bhargava, Devendra S; Shrihari, S

    2009-10-01

    Settled solids from effluents discharged into a river system, undergoing decomposition at the river bottom, form an appreciable internal nutrient source for the biological activities in the river system. During the stabilization of benthal deposits, a variety of nutrients are released into the overlying waters. The exchange between sediment and overlying waters is a major component of the nitrogen and phosphorous cycles in the natural waters. The releases of such nutrients is a surface phenomenon, regulated by the conditions of benthal sludge layers, flow rate of overlying waters, etc. The rate of ammonia nitrogen release manifested an optimum low value when benthal sludge depth was 0.2 m, but was not influenced by the flow rate of overlying water and h/d ratios. The rate of phosphate release from benthal sludge was independent of depth of benthal sludge, flow rate and h/d ratios. The nutrients in the benthal sludge layers were increasing with time, and were concentrated at a layer 10 cm below the top surface. The nutrients release (percent of nutrient remaining in top benthal sludge layers) decreased with time and became almost constant after about 40 days. The nutrients release under continuously accumulating conditions of benthal sludge and the effects of frequency of addition have been discussed in this paper. The nutrients release was less when the frequency of addition was less.

  7. Modelling nutrient cycling in forest ecosystems; Modellering av naeringssyklus i skogoekosystemer

    Energy Technology Data Exchange (ETDEWEB)

    Kvindesland, Sheila H.S.B.

    1997-12-31

    Acid deposition`s threat to fresh water and forest environments became an issue in the late 1960s. Acid deposition and forest nutrient cycling then began to be researched in greater co-operation. This thesis studies nutrient cycling processes in Norway spruce forests, emphasizing the effects on soil chemical properties, soil solution chemistry and streamwater chemistry. It investigates the effects of different aged stands on nutrient cycling and sets up nutrient budgets of the base cations and nitrogen at two sites in Norway. It also selects, documents, calibrates, tests and improves nutrient cycling models for use in Norwegian forests. 84 refs., 44 figs., 46 tabs.

  8. Nutrient balances in the forest energy cycle

    International Nuclear Information System (INIS)

    Olsson, Bengt

    2006-02-01

    In Sweden, recycling of stabilised wood-ashes to forests is considered to compensate for nutrient removals from whole-tree harvesting (i.e. use of harvest residues - slash - for energy purposes). This study has analysed nutrient fluxes through the complete forest energy cycle and estimated mass balances of nutrients in harvested biomass with those in ashes, to investigate the realism in large-scale nutrient compensation with wood-ash. Expected nutrient fluxes from forests through energy plants were calculated based on nutrient and biomass data of forest stands in the Nordic countries, and from data on nutrient fluxes through CFB-plants. The expected stoichiometric composition of wood-ashes was compared with the composition of CFB-fly ashes from various Swedish energy plants. Nutrient contents for different tree fractions were calculated to express the average nutrient concentrations in slash and stems with bark, respectively. A nutrient budget synthesis of the effects of whole-tree harvesting on base cation turnover in the following stand was presented for two experimental sites. Major conclusions from the study are: In the CFB-scenario, where the bottom ash is deposited and only the fly ash can be applied to forests, the fly ash from the slash do not meet the demands for nutrient compensation for slash harvesting. Stem material (50% wood, 50% bark) must be added at equivalent amounts, as the slash to produce the amounts of fly ash needed for compensation of slash harvesting. In the scenario where more stem material was added (75% of total fuel load), the amounts of fly ashes produced hardly compensated for nutrient removals with both stem and slash harvesting. The level of nutrient compensation was lowest for potassium. The stoichiometric nutrient composition of CFB-fly ashes from Swedish energy plants is not similar with the nutrient composition of tree biomass. The higher Ca/P ratio in ashes is only partly explained by the mixture of fuels (e.g. increasing bark

  9. Recovery from disturbance requires resynchronization of ecosystem nutrient cycles.

    Science.gov (United States)

    Rastetter, E B; Yanai, R D; Thomas, R Q; Vadeboncoeur, M A; Fahey, T J; Fisk, M C; Kwiatkowski, B L; Hamburg, S P

    2013-04-01

    Nitrogen (N) and phosphorus (P) are tightly cycled in most terrestrial ecosystems, with plant uptake more than 10 times higher than the rate of supply from deposition and weathering. This near-total dependence on recycled nutrients and the stoichiometric constraints on resource use by plants and microbes mean that the two cycles have to be synchronized such that the ratio of N:P in plant uptake, litterfall, and net mineralization are nearly the same. Disturbance can disrupt this synchronization if there is a disproportionate loss of one nutrient relative to the other. We model the resynchronization of N and P cycles following harvest of a northern hardwood forest. In our simulations, nutrient loss in the harvest is small relative to postharvest losses. The low N:P ratio of harvest residue results in a preferential release of P and retention of N. The P release is in excess of plant requirements and P is lost from the active ecosystem cycle through secondary mineral formation and leaching early in succession. Because external P inputs are small, the resynchronization of the N and P cycles later in succession is achieved by a commensurate loss of N. Through succession, the ecosystem undergoes alternating periods of N limitation, then P limitation, and eventually co-limitation as the two cycles resynchronize. However, our simulations indicate that the overall rate and extent of recovery is limited by P unless a mechanism exists either to prevent the P loss early in succession (e.g., P sequestration not stoichiometrically constrained by N) or to increase the P supply to the ecosystem later in succession (e.g., biologically enhanced weathering). Our model provides a heuristic perspective from which to assess the resynchronization among tightly cycled nutrients and the effect of that resynchronization on recovery of ecosystems from disturbance.

  10. Projections of Atmospheric Nutrient Deposition to the Chesapeake Bay Watershed

    Science.gov (United States)

    Atmospheric deposition remains one of the largest loadings of nutrients to the Chesapeake Bay watershed. The interplay between future land use, climate, and emission changes, however, will cause shifts in the future nutrient deposition regime (e.g., oxidized vs. reduced nitrogen...

  11. Forest management and nutrient cycling in eastern hardwoods

    Science.gov (United States)

    James H. Patric; David W. Smith

    1975-01-01

    The literature was reviewed for reports on nutrient cycling in the eastern deciduous forest, particularly with respect to nitrogen, and for effects of forest management on the nutrient cycle. Although most such research has dealt with conifers, a considerable body of literature relates to hardwoods. Usually, only those references that dealt quantitatively with nutrient...

  12. Nutrient cycle benchmarks for earth system land model

    Science.gov (United States)

    Zhu, Q.; Riley, W. J.; Tang, J.; Zhao, L.

    2017-12-01

    Projecting future biosphere-climate feedbacks using Earth system models (ESMs) relies heavily on robust modeling of land surface carbon dynamics. More importantly, soil nutrient (particularly, nitrogen (N) and phosphorus (P)) dynamics strongly modulate carbon dynamics, such as plant sequestration of atmospheric CO2. Prevailing ESM land models all consider nitrogen as a potentially limiting nutrient, and several consider phosphorus. However, including nutrient cycle processes in ESM land models potentially introduces large uncertainties that could be identified and addressed by improved observational constraints. We describe the development of two nutrient cycle benchmarks for ESM land models: (1) nutrient partitioning between plants and soil microbes inferred from 15N and 33P tracers studies and (2) nutrient limitation effects on carbon cycle informed by long-term fertilization experiments. We used these benchmarks to evaluate critical hypotheses regarding nutrient cycling and their representation in ESMs. We found that a mechanistic representation of plant-microbe nutrient competition based on relevant functional traits best reproduced observed plant-microbe nutrient partitioning. We also found that for multiple-nutrient models (i.e., N and P), application of Liebig's law of the minimum is often inaccurate. Rather, the Multiple Nutrient Limitation (MNL) concept better reproduces observed carbon-nutrient interactions.

  13. Impact of arbuscular mycorrhizal fungi on nutrient cycling in agroecosystems

    NARCIS (Netherlands)

    Köhl, L.

    2016-01-01

    The intensification of agricultural production to meet global food demands has led to excessive nutrient leaching from agricultural areas. These losses have negative environmental impacts and pose a waste of valuable fertilizer. Soil biota are essential for nutrient cycling in soil and thus could be

  14. Shifts in lake N: P stoichiometry and nutrient limitation driven by atmospheric nitrogen deposition

    Science.gov (United States)

    Elser, J.J.; Andersen, T.; Baron, Jill S.; Bergstrom, A.-K.; Jansson, M.; Kyle, M.; Nydick, K.R.; Steger, L.; Hessen, D.O.

    2009-01-01

    Human activities have more than doubled the amount of nitrogen (N) circulating in the biosphere. One major pathway of this anthropogenic N input into ecosystems has been increased regional deposition from the atmosphere. Here we show that atmospheric N deposition increased the stoichiometric ratio of N and phosphorus (P) in lakes in Norway, Sweden, and Colorado, United States, and, as a result, patterns of ecological nutrient limitation were shifted. Under low N deposition, phytoplankton growth is generally N-limited; however, in high-N deposition lakes, phytoplankton growth is consistently P-limited. Continued anthropogenic amplification of the global N cycle will further alter ecological processes, such as biogeochemical cycling, trophic dynamics, and biological diversity, in the world's lakes, even in lakes far from direct human disturbance.

  15. Impact of biomass burning on nutrient deposition to the global ocean

    Science.gov (United States)

    Kanakidou, Maria; Myriokefalitakis, Stelios; Daskalakis, Nikos; Mihalopoulos, Nikolaos; Nenes, Athanasios

    2017-04-01

    Atmospheric deposition of trace constituents, both of natural and anthropogenic origin, can act as a nutrient source into the open ocean and affect marine ecosystem functioning and subsequently the exchange of CO2 between the atmosphere and the global ocean. Dust is known as a major source of nutrients (Fe and P) into the atmosphere, but only a fraction of these nutrients is released in soluble form that can be assimilated by the ecosystems. Dust is also known to enhance N deposition by interacting with anthropogenic pollutants and neutralisation of part of the acidity of the atmosphere by crustal alkaline species. These nutrients have also primary anthropogenic sources including combustion emissions. The global atmospheric N [1], Fe [2] and P [3] cycles have been parameterized in the global 3-D chemical transport model TM4-ECPL, accounting for inorganic and organic forms of these nutrients, for all natural and anthropogenic sources of these nutrients including biomass burning, as well as for the link between the soluble forms of Fe and P atmospheric deposition and atmospheric acidity. The impact of atmospheric acidity on nutrient solubility has been parameterised based on experimental findings and the model results have been evaluated by extensive comparison with available observations. In the present study we isolate the significant impact of biomass burning emissions on these nutrients deposition by comparing global simulations that consider or neglect biomass burning emissions. The investigated impact integrates changes in the emissions of the nutrients as well as in atmospheric oxidants and acidity and thus in atmospheric processing and secondary sources of these nutrients. The results are presented and thoroughly discussed. References [1] Kanakidou M, S. Myriokefalitakis, N. Daskalakis, G. Fanourgakis, A. Nenes, A. Baker, K. Tsigaridis, N. Mihalopoulos, Past, Present and Future Atmospheric Nitrogen Deposition, Journal of the Atmospheric Sciences (JAS-D-15

  16. Influence of soil structure on nutrient cycling using microfluidic techniques

    Science.gov (United States)

    Arellano Caicedo, Carlos; Aleklett, Kristin; Ohlsson, Pelle; Hammer, Edith

    2017-04-01

    The rising of atmospheric CO2 levels and its effects on global warming make it necessary to understand the elements that regulate such levels and furthermore try to slow down the CO2 accumulation in the atmosphere. The exchange of carbon between soil and atmosphere plays a significant role in the atmospheric carbon budget. Soil organisms deposit organic compounds on and in soil aggregates, either as exudates or dead remains. Much of this dead organic material is quickly recycled, but a portion, however, will stay in the soil for long term. Evidence suggests that micro-scale biogeochemical interactions could play a highly significant role in degradation or persistence of organic matter in soils, thus, soil physical structure might play a decisive role in preventing accessibility of nutrients to microorganisms. For studying effects of spatial microstructure on soil nutrient cycles, we have constructed artificial habitats for microbes that simulate soil structures. Microfluidic, so called Lab-on-a-chip technologies, are one of the tools used to achieve our purpose. Such micro-habitats consist of pillar structures of difference density and surface area, tunnels with increasing depth, and mazes of increasing complexity to simulate different stages of soil aggregation. Using microscopy and analytical chemistry, we can follow the growth of microorganisms inoculated into the "soil chip" as well as the chemical degradation of organic matter compounds provided as nutrient source. In this way, we want to be able to predict how soil structure influences soil microbial activity leading to different effects on the carbon cycle. Our first results of a chip inoculated with natural soil showed a succession of organisms colonizing channels leading to dead-end arenas, starting with a high presence of bacteria inside the chip during the first days. Fungal hyphae growth gradually inside the channels until it finally occupied the big majority of the spaces isolating bacteria which

  17. Strong hydrological control on nutrient cycling of subtropical rainforests

    Science.gov (United States)

    Lin, T. C.; Chang, C. T.; Huang, J. C.; Wang, L.; Lin, N. H.

    2016-12-01

    Forest nutrient cycling is strongly controlled by both biological and hydrological factors. However, based on a close examination of earlier reports, we highlight the role of hydrological control on nutrient cycling at a global scale and is more important at humid tropical and subtropical forests. we analyzed the nutrient budget of precipitation input and stream water output from 1994 to 2013 in a subtropical forest in Taiwan and conducted a data synthesis using results from 32 forests across the globe. The results revealed that monthly input and output of ions were positively correlated with water quantity, indicating hydrological control on nutrient cycling. Hydrological control is also evident from the greater ions export via stream water during the warm and wet growing season. The synthesis also illustrates that strong hydrological control leads to lower nitrogen retention and greater net loss of base cations in humid regions, particularly in the humid tropical and subtropical forests. Our result is of great significance in an era of global climate change because climate change could directly affect ecosystem nutrient cycling particularly in the tropics through changes in patterns of precipitation regime.

  18. Hydromorphological control of nutrient cycling in complex river floodplain systems

    Science.gov (United States)

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

    2009-04-01

    Riparian zones and floodplains are key components within river ecosystems controlling nutrient cycling by promoting transformation processes and thus, act as biogeochemical hot spots. The intensity of these processes depends on the exchange conditions (the connectivity) with the main channel and the morphological setting of the water bodies. At the landscape scale, three interrelated principles of hydromorphological dynamics can be formulated regarding the cycling and transfer of carbon and nutrients in large rivers ecosystems: a) The mode of carbon and nutrient delivery affects ecosystem functioning; b) Increasing residence time and contact area impact nutrient transformation; c) Floods and droughts are natural events that strongly influence pathways of carbon and nutrient cycling. These three principles of hydromorphological dynamics control the nutrient uptake and retention and are linked over different temporal and spatial scales. All three factors can be strongly affected by natural disturbances or anthropogenic impacts, through a change in either the water regime or the geomorphologic setting of the river valley. Any change in natural water regimes will affect the biogeochemistry of riparian zones and floodplains as well as their ability to cycle and mitigate nutrient fluxes originating from upstream and/or upslope. Especially these areas have been altered by river regulation and land use changes over the last 200 years leading to the deterioration of the functioning of these compartments within the riverine landscape. The resulting deficits have prompted rehabilitation and restoration measures aiming to increase the spatial heterogeneity, the complexity, of these ecosystems. Yet, a more integrated approach is needed considering the present status of nutrient dynamics and the effects of restoration measures at different scales. The present paper analyses the effects of river side-arm restoration on ecosystem functions within the side-arm and highlights

  19. Temporal variability of foliar nutrients: responses to nitrogen deposition and prescribed fire in a temperate steppe

    Science.gov (United States)

    Lü, Xiao-Tao; Reed, Sasha C.; Hou, Shuang-Li; Hu, Yan-Yu; Wei, Hai-Wei; Lü, Fu-Mei; Cui, Qiang; Han, Xing Guo

    2017-01-01

    Plant nutrient concentrations and stoichiometry drive fundamental ecosystem processes, with important implications for primary production, diversity, and ecosystem sustainability. While a range of evidence exists regarding how plant nutrients vary across spatial scales, our understanding of their temporal variation remains less well understood. Nevertheless, we know nutrients regulate plant function across time, and that important temporal controls could strongly interact with environmental change. Here, we report results from a 3-year assessment of inter-annual changes of foliar nitrogen (N) and phosphorus (P) concentrations and stoichiometry in three dominant grasses in response to N deposition and prescribed fire in a temperate steppe of northern China. Foliar N and P concentrations and their ratios varied greatly among years, with this temporal variation strongly related to inter-annual variation in precipitation. Nitrogen deposition significantly increased foliar N concentrations and N:P ratios in all species, while fire significantly altered foliar N and P concentrations but had no significant impacts on N:P ratios. Generally, N addition enhanced the temporal stability of foliar N and decreased that of foliar P and of N:P ratios. Our results indicate that plant nutrient status and response to environmental change are temporally dynamic and that there are differential effects on the interactions between environmental change drivers and timing for different nutrients. These responses have important implications for consideration of global change effects on plant community structure and function, management strategies, and the modeling of biogeochemical cycles under global change scenarios.

  20. Biomass decomposition and nutrient release from black oat and hairy vetch residues deposited in a vineyard

    Directory of Open Access Journals (Sweden)

    Paulo Ademar Avelar Ferreira

    2014-10-01

    Full Text Available A significant quantity of nutrients in vineyards may return to the soil each year through decomposition of residues from cover plants. This study aimed to evaluate biomass decomposition and nutrient release from residues of black oats and hairy vetch deposited in the vines rows, with and without plastic shelter, and in the between-row areas throughout the vegetative and productive cycle of the plants. The study was conducted in a commercial vineyard in Bento Gonçalves, RS, Brazil, from October 2008 to February 2009. Black oat (Avena strigosa and hairy vetch (Vicia villosa residues were collected, subjected to chemical (C, N, P, K, Ca, and Mg and biochemical (cellulose - Cel, hemicellulose - Hem, and lignin - Lig content analyses, and placed in litter bags, which were deposited in vines rows without plastic shelter (VPRWS, in vines rows with plastic shelter (VPRS, and in the between-row areas (BR. We collected the residues at 0, 33, 58, 76, and 110 days after deposition of the litter bags, prepared the material, and subjected it to analysis of total N, P, K, Ca, and Mg content. The VPRS contained the largest quantities and percentages of dry matter and residual nutrients (except for Ca in black oat residues from October to February, which coincides with the period from flowering up to grape harvest. This practice led to greater protection of the soil surface, avoiding surface runoff of the solution derived from between the rows, but it retarded nutrient cycling. The rate of biomass decomposition and nutrient release from hairy vetch residues from October to February was not affected by the position of deposition of the residues in the vineyard, which may especially be attributed to the lower values of the C/N and Lig/N ratios. Regardless of the type of residue, black oat or hairy vetch, the greatest decomposition and nutrient release mainly occurred up to 33 days after deposition of the residues on the soil surface, which coincided with the

  1. Potash—A vital agricultural nutrient sourced from geologic deposits

    Science.gov (United States)

    Yager, Douglas B.

    2016-11-15

    This report summarizes the primary sources of potash in the United States. Potash is an essential nutrient that, along with phosphorus and nitrogen, is used as fertilizer for growing crops. Plants require sufficient potash to activate enzymes, which in turn catalyze chemical reactions important for water uptake and photosynthesis. When potassium is available in quantities necessary for healthy plant growth, disease resistance and physical quality are improved and crop yield and shelf life are increased. Potash is a water-soluble compound of potassium formed by geologic and hydrologic processes. The principal potash sources discussed are the large, stratiform deposits that formed during retreat and evaporation of intracontinental seas. The Paradox, Delaware, Holbrook, Michigan, and Williston sedimentary basins in the United States are examples where extensive potash beds were deposited. Ancient marine-type potash deposits that are close to the surface can be mined using conventional underground mining methods. In situ solution mining can be used where beds are too deep, making underground mining cost-prohibitive, or where underground mines are converted to in situ solution mines. Quaternary brine is another source of potash that is recovered by solar evaporation in manmade ponds. Groundwater from Pleistocene Lake Bonneville (Wendover, Utah) and the present-day Great Salt Lake in Utah are sources of potashbearing brine. Brine from these sources pumped to solar ponds is evaporated and potash concentrated for harvesting, processing, and refinement. Although there is sufficient potash to meet near-term demand, the large marine-type deposits are either geographically restricted to a few areas or are too deep to easily mine. Other regions lack sources of potash brine from groundwater or surface water. Thus, some areas of the world rely heavily on potash imports. Political, economic, and global population pressures may limit the ability of some countries from securing

  2. A Comparative-Study on Nutrient Cycling in Wet Heathland Ecosystems.2.Litter Decomposition and Nutrient Mineralization

    NARCIS (Netherlands)

    Berendse, F.; Bobbink, R.; Rouwenhorst, G.

    1989-01-01

    The concept of the relative nutrient requirement (L n) that was introduced in the first paper of this series is used to analyse the effects of the dominant plant population on nutrient cycling and nutrient mineralization in wet heathland ecosystems. A distinction is made between the effect that the

  3. Biomass and nutrient cycling by winter cover crops

    Directory of Open Access Journals (Sweden)

    Jana Koefender

    Full Text Available ABSTRACT Cover crops are of fundamental importance for the sustainability of the no-tillage system, to ensure soil coverage and to provide benefits for the subsequent crop. The objective of this study was to evaluate the production of biomass and the content and accumulation of nutrients by winter cover crops. The experimental design used in the experiment was a randomized complete block with four replications and six treatments: oilseed radish, vetch, black oats, vetch + black oats, vetch + oilseed radish and fallow. Black oat, oilseed radish in single cultivation and black oat + vetch and vetch + oilseed radish intercroppings showed higher dry matter production. Vetch + oilseed radish intercropping demonstrates higher performance regarding cycling of nutrients, with higher accumulations of N, P, K, Ca, Mg, S, Cu, Zn, Fe, Na and B.

  4. Annual litterfall dynamics and nutrient deposition depending on elevation and land use at Mt. Kilimanjaro

    Science.gov (United States)

    Becker, J.; Pabst, H.; Mnyonga, J.; Kuzyakov, Y.

    2015-10-01

    Litterfall is one of the major pathways connecting above- and below-ground processes. The effects of climate and land-use change on carbon (C) and nutrient inputs by litterfall are poorly known. We quantified and analyzed annual patterns of C and nutrient deposition via litterfall in natural forests and agroforestry systems along the unique elevation gradient of Mt. Kilimanjaro. Tree litter in three natural (lower montane, Ocotea and Podocarpus forests), two sustainably used (homegardens) and one intensively managed (shaded coffee plantation) ecosystems was collected on a biweekly basis from May 2012 to July 2013. Leaves, branches and remaining residues were separated and analyzed for C and nutrient contents. The annual pattern of litterfall was closely related to rainfall seasonality, exhibiting a large peak towards the end of the dry season (August-October). This peak decreased at higher elevations with decreasing rainfall seasonality. Macronutrients (N, P, K) in leaf litter increased at mid elevation (2100 m a.s.l.) and with land-use intensity. Carbon content and micronutrients (Al, Fe, Mn, Na) however, were unaffected or decreased with land-use intensity. While leaf litterfall decreased with elevation, total annual input was independent of climate. Compared to natural forests, the nutrient cycles in agroforestry ecosystems were accelerated by fertilization and the associated changes in dominant tree species.

  5. Effects of mountain tea plantations on nutrient cycling at upstream watersheds

    Science.gov (United States)

    Lin, T.-C.; Shaner, P.-J. L.; Wang, L.-J.; Shih, Y.-T.; Wang, C.-P.; Huang, G.-H.; Huang, J.-C.

    2015-11-01

    The expansion of agriculture to rugged mountains can exacerbate negative impacts of agricultural activities on ecosystem function. In this study, we monitored streamwater and rainfall chemistry of mountain watersheds at the Feitsui Reservoir Watershed in northern Taiwan to examine the effects of agriculture on watershed nutrient cycling. We found that the greater the proportion of tea plantation cover, the higher the concentrations of fertilizer-associated ions (NO3-, K+) in streamwater of the four mountain watersheds examined; on the other hand, the concentrations of the ions that are rich in soils (SO42-, Ca2+, Mg2+) did not increase with the proportion of tea plantation cover, suggesting that agriculture enriched fertilizer-associated nutrients in streamwater. Of the two watersheds for which rainfall chemistry was available, the one with higher proportion of tea plantation cover had higher concentrations of ions in rainfall and retained less nitrogen in proportion to input compared to the more pristine watershed, suggesting that agriculture can influence atmospheric deposition of nutrients and a system's ability to retain nutrients. As expected, we found that a forested watershed downstream of agricultural activities can dilute the concentrations of NO3- in streamwater by more than 70 %, indicating that such a landscape configuration helps mitigate nutrient enrichment in aquatic systems even for watersheds with steep topography. We estimated that tea plantation at our study site contributed approximately 450 kg ha-1 yr-1 of NO3-N via streamwater, an order of magnitude greater than previously reported for agricultural lands around the globe, which can only be matched by areas under intense fertilizer use. Furthermore, we constructed watershed N fluxes to show that excessive leaching of N, and additional loss to the atmosphere via volatilization and denitrification can occur under intense fertilizer use. In summary, this study demonstrated the pervasive impacts of

  6. A comparative study on nutrient cycling in wet heathland ecosystems : II. Litter decomposition and nutrient mineralization.

    Science.gov (United States)

    Berendse, Frank; Bobbink, Roland; Rouwenhorst, Gerrit

    1989-03-01

    The concept of the relative nutrient requirement (L n ) that was introduced in the first paper of this series is used to analyse the effects of the dominant plant population on nutrient cycling and nutrient mineralization in wet heathland ecosystems. A distinction is made between the effect that the dominant plant species has on (1) the distribution of nutrients over the plant biomass and the soil compartment of the ecosystem and (2) the recirculation rate of nutrients. The first effect of the dominant plant species can be calculated on the basis of the δ/k ratio (which is the ratio of the relative mortality to the decomposition constant). The second effect can be analysed using the relative nutrient requirement (L n ). The mass loss and the changes in the amounts of N and P in decomposing above-ground and below-ground litter produced by Erica tetralix and Molinia caerulea were measured over three years. The rates of mass loss from both above-ground and below-ground litter of Molinia were higher than those from Erica litter. After an initial leaching phase, litter showed either a net release or a net immobilization of nitrogen or phosphorus that depended on the initial concentrations of these nutrients. At the same sites, mineralization of nitrogen and phosphorus were measured for two years both in communities dominated by Molinia and in communities dominated by Erica. There were no clear differences in the nitrogen mineralization, but in one of the two years, phosphate mineralization in the Molinia-community was significantly higher. On the basis of the theory that was developed, mineralization rates and ratios between amounts of nutrients in plant biomass and in the soil were calculated on the basis of parameters that were independently measured. There was a reasonable agreement between predicted and measured values in the Erica-communities. In the Molinia-communities there were large differences between calculated and measured values, which was explained by the

  7. Floodplain trapping and cycling compared to streambank erosion of sediment and nutrients in an agricultural watershed

    Science.gov (United States)

    Gillespie, Jaimie; Noe, Gregory; Hupp, Cliff R.; Gellis, Allen; Schenk, Edward R.

    2018-01-01

    Floodplains and streambanks can positively and negatively influence downstream water quality through interacting geomorphic and biogeochemical processes. Few studies have measured those processes in agricultural watersheds. We measured inputs (floodplain sedimentation and dissolved inorganic loading), cycling (floodplain soil nitrogen [N] and phosphorus [P] mineralization), and losses (bank erosion) of sediment, N, and P longitudinally in stream reaches of Smith Creek, an agricultural watershed in the Valley and Ridge physiographic province. All study reaches were net depositional (floodplain deposition > bank erosion), had high N and P sedimentation and loading rates to the floodplain, high soil concentrations of N and P, and high rates of floodplain soil N and P mineralization. High sediment, N, and P inputs to floodplains are attributed to agricultural activity in the region. Rates of P mineralization were much greater than those measured in other studies of nontidal floodplains that used the same method. Floodplain connectivity and sediment deposition decreased longitudinally, contrary to patterns in most watersheds. The net trapping function of Smith Creek floodplains indicates a benefit to water quality. Further research is needed to determine if future decreases in floodplain deposition, continued bank erosion, and the potential for nitrate leaching from nutrient-enriched floodplain soils could pose a long-term source of sediment and nutrients to downstream rivers.

  8. Productivity and nutrient cycling in bioenergy cropping systems

    Science.gov (United States)

    Heggenstaller, Andrew Howard

    One of the greatest obstacles confronting large-scale biomass production for energy applications is the development of cropping systems that balance the need for increased productive capacity with the maintenance of other critical ecosystem functions including nutrient cycling and retention. To address questions of productivity and nutrient dynamics in bioenergy cropping systems, we conducted two sets of field experiments during 2005-2007, investigating annual and perennial cropping systems designed to generate biomass energy feedstocks. In the first experiment we evaluated productivity and crop and soil nutrient dynamics in three prototypical bioenergy double-crop systems, and in a conventionally managed sole-crop corn system. Double-cropping systems included fall-seeded forage triticale (x Triticosecale Wittmack), succeeded by one of three summer-adapted crops: corn (Zea mays L.), sorghum-sudangrass [Sorghum bicolor (L.) Moench], or sunn hemp (Crotalaria juncea L.). Total dry matter production was greater for triticale/corn and triticale/sorghum-sudangrass compared to sole-crop corn. Functional growth analysis revealed that photosynthetic duration was more important than photosynthetic efficiency in determining biomass productivity of sole-crop corn and double-crop triticale/corn, and that greater yield in the tiritcale/corn system was the outcome of photosynthesis occurring over an extended duration. Increased growth duration in double-crop systems was also associated with reductions in potentially leachable soil nitrogen relative to sole-crop corn. However, nutrient removal in harvested biomass was also greater in the double-crop systems, indicating that over the long-term, double-cropping would mandate increased fertilizer inputs. In a second experiment we assessed the effects of N fertilization on biomass and nutrient partitioning between aboveground and belowground crop components, and on carbon storage by four perennial, warm-season grasses: big bluestem

  9. Evergreen shrub traits and peatland carbon cycling under high nutrient load

    Science.gov (United States)

    Larmola, Tuula; Bui, Vi; Bubier, Jill L.; Wang, Meng; Murphy, Meaghan; Moore, Tim R.

    2016-04-01

    The reactive nitrogen (N) assimilated by plants is usually invested in chlorophyll to improve light harvesting capacity and in soluble proteins such as Rubisco to enhance carbon (C) assimilation. We studied the effects of simulated atmospheric N deposition on different traits of two evergreen shrubs Chamaedaphne calyculata and Rhododendron groenlandicum in a nutrient-poor Mer Bleue Bog, Canada that has been fertilized with N as NO3 and NH4 (2-8 times ambient annual wet deposition) with or without phosphorus (P) and potassium (K) for 7-12 years. We examined how nutrient addition influences the plant performance at leaf and canopy level and linked the trait responses with ecosystem C cycling. At the leaf level, we measured physiological and biochemical traits: CO2 exchange and chlorophyll fluorescence, an indicator of plant stress in terms of light harvesting capacity; and to study changes in photosynthetic nutrient use efficiency, we also determined the foliar chlorophyll, N, and P contents. At the canopy level, we examined morphological and phenological traits: growth responses and leaf longevity during two growing seasons. Regardless of treatment, the majority of leaves showed no signs of stress in terms of light harvesting capacity. The plants were N saturated: with increasing foliar N content, the higher proportion of N was not used in photosynthesis. Foliar net CO2 assimilation rates did not differ significantly among treatments, but the additions of N, P, and K together resulted in higher respiration rates. The analysis of the leaf and canopy traits showed that the two shrubs had different strategies: C. calyculata was more responsive to nutrient additions, more deciduous-like, whereas R. groenlandicum maintained evergreen features under nutrient load, shedding its leaves even later in the season. In all, simulated atmospheric N deposition did not benefit the photosynthetic apparatus of the dominant shrubs, but resulted in higher foliar respiration

  10. Impacts of Dry Atmospheric Deposition on Aquatic Systems - Nutrients, Trace Metals and Lead Isotopes

    OpenAIRE

    Chien, Chia-Te

    2017-01-01

    Atmospheric deposition is a source of new N, P and trace metals to the ocean and water bodies on land. Nutrient and trace metal inputs from atmospheric deposition have been shown to induce phytoplankton growth and impact water chemistry. The three chapters presented in this thesis examine dry atmospheric deposition impacts on phytoplankton and water chemistry including: (1) How African dust impact phytoplankton growth at the low nutrient low chlorophyll (LNLC) ocean off Barbados; (2) Evaluate...

  11. Mass-Balance Constraints on Nutrient Cycling in Tropical Seagrass Beds

    NARCIS (Netherlands)

    Erftemeijer, P.L.A.; Middelburg, J.J.

    1995-01-01

    A relatively simple mass balance model is presented to study the cycling of nutrients (nitrogen and phosphorus) in tropical seagrass beds. The model is based on quantitative data on nutrient availability, seagrass primary production, community oxygen metabolism, seagrass tissue nutrient contents,

  12. Nutrient Cycling in Primary, Secondary Forests and Cocoa ...

    African Journals Online (AJOL)

    USER

    Abstract. Primary forest (reserved area), secondary forest and cocoa plantation land uses characterize uplands of Dwinyama watershed in Ghana within the dry semi-deciduous forest zone. The nutrients recycled in the land uses were studied through leaf litter fall, nutrient release, nutrient fluxes estimation and topsoil ...

  13. Effects of afforestation and deforestation on the deposition, cycling and leaching of elements

    DEFF Research Database (Denmark)

    Rasmussen, L.

    1998-01-01

    . In parallel, changes in land use and management practice have contributed to changes in the cycling of elements and in soil conditions. Afforestation and deforestation can also change atmospheric dry deposition and the processes controlling the mobility of nutrients and acidifying substances. Different types...... of forest management such as choice of tree species, deforestation by clear-felling or selection forest, fertilization, liming, sludge and compost addition, etc. will influence the leaching of nutrients from forest ecosystems. Since nitrogen is assumed to be the most important macronutrient in European...... to acidification of soils. The critical load for atmospheric deposition of nitrogen can be evaluated in relation to nitrogen saturation, leaching, afforestation/deforestation, stand history and environmental conditions. In such assessments the chemical forms of nitrogen, spatial variability and time resolutions...

  14. The elusive role of soil quality in nutrient cycling: a review

    NARCIS (Netherlands)

    Schroder, Jaap; Schulte, R.P.O.; Creamer, R.E.; Delgado, A.; Leeuwen, Van J.; Lehtinen, T.; Rutgers, M.; Spiegel, H.; Staes, J.; Tóth, G.; Wall, D.P.

    2016-01-01

    Cycling of nutrients, including nitrogen and phosphorus, is one of the ecosystem services we expect agricultural soils to deliver. Nutrient cycling incorporates the reuse of agricultural, industrial and municipal organic residues that, misleadingly, are often referred to as ‘wastes’. The present

  15. Litterfall dynamics and nutrient deposition at different elevation and land use levels on Mt. Kilimanjaro, Tanzania

    Science.gov (United States)

    Becker, Joscha; Pabst, Holger; Mnyonga, James; Kuzyakov, Yakov

    2014-05-01

    One of the major pathways that connect above- and belowground nutrient and carbon stocks in forest ecosystems is litterfall. Depending on climate, tree species composition and stand structure it varies considerably between different ecosystems. Another driving factor that is known to affect ecosystem cycles is the level of anthropogenic disturbance such as land use. In case of tropical regions this is often present as the transformation from rainforests to plantation economy and sustainable agroforestry. The objective of this study was to quantify and determine patterns of carbon and nutrient deposition via tree litterfall in natural and anthropogenically affected forest ecosystems along an elevation gradient of Mt. Kilimanjaro. Tree litter of three natural (lower montane forest), two sustainably used (home gardens) and one intensively managed (shaded coffee plantation) ecosystem was collected on a biweekly basis from May 2012 to July 2013. Samples were separated into leaves, branches and remaining residues, dried and weighted. Carbon and nutrient content were measured in leave samples. We found that the overall annual pattern of litterfall was closely related to rainfall exhibiting a large peak during the dry season. Albeit visible on all plots, this characteristic decreased with elevation. No consistent patterns were found for other components than leaves. Total annual litter mainly consisted of leaf litter and ranges from 4639 kg/ha to 10673 kg/ha for all vegetation types. Flowers, fruits, etc. make up roughly 20% of total litter. Highest and lowest values occurred at home gardens and could not be significantly related to land use or elevation levels. Chemistry though differed between natural and used forest plots. N, P and K contents increased significantly with usage intensity while Mn decreased and C is more or less unaffected. We conclude that on the southern slope of Mt. Kilimanjaro, short term variations in litterfall are related to seasonal climatic

  16. Isotope-aided studies of nutrient cycling and soil fertility assessment in humid pasture systems

    International Nuclear Information System (INIS)

    Wilkinson, S.R.

    1983-01-01

    Maintenance of primary productivity in grazed ecosystems depends on the orderly cycling of mineral nutrients. Potential applications of nuclear techniques to the study of soil fertility assessment and nutrient cycling are discussed for the plant nutrients N, P, K and S. The bioavailability of extrinsic and intrinsic sources of mineral nutrients are also discussed. With improvements in analytical technology, it appears feasible to use 15 N in grazed pasture ecosystems for N cycling studies. Sulphur cycling in soil/plant/grazing animal systems has been successfully studied, and further opportunities exist using 35 S to study nutrient flows in grazed grassland systems. Opportunities also appear for increased application of tracer technology in the evaluation of mineral intakes and mineral bioavailability to ruminants grazing semi-arid grassland herbage under native soil fertility, with supplemental fertilization, and in the evaluation of mineral supplementation procedures. Root system distribution and function also can be studied advantageously using tracer techniques. (author)

  17. Calculation of growth per cycle (GPC) of atomic layer deposited ...

    Indian Academy of Sciences (India)

    Home; Journals; Pramana – Journal of Physics; Volume 82; Issue 3. Calculation of growth per cycle (GPC) of atomic layer deposited aluminium oxide nanolayers and dependence of GPC on surface OH concentration. Anu Philip Subin Thomas K Rajeev Kumar. Research Articles Volume 82 Issue 3 March 2014 pp 563-569 ...

  18. Soluble Nutrient and Trace Metal Fluxes from Aerosol Dry Deposition to Elkhorn Slough, CA

    Science.gov (United States)

    Gray, E. T.; Paytan, A.; Haskins, J.

    2009-12-01

    Atmospheric deposition has been widely recognized as a source of pollutants and nutrients to coastal ecosystems. Specifically, deposition includes nitrogen compounds, sulfur compounds, mercury, pesticides, phosphate, trace metals and other toxic compounds that can travel great distances in aerosols. These components can come from both natural (volcanoes, mineral dust, forest fires) and anthropogenic (fossil fuels, chemical byproducts, incineration of waste) sources. These pollutants may affect ecosystem health and water quality with environmental impacts such as eutrophication, contaminated fish and harmful algal blooms. In this study we focus on dry deposition to Elkhorn Slough, California. Size fractionated aerosol samples (PM 2.5 and PM 10) collected continuously over a seven day period using a cascade impactor are used along with a deposition model to determine the soluble nutrient and trace metal fluxes on the Elkhorn Slough ecosystem. Atmospheric deposition inputs will be compared to other sources and their potential impact evaluated.

  19. The contribution of occult precipitation to nutrient deposition on the west coast of South Africa.

    Directory of Open Access Journals (Sweden)

    Justine M Nyaga

    Full Text Available The Strandveld mediterranean-ecosystem of the west coast of South Africa supports floristically diverse vegetation growing on mostly nutrient-poor aeolian sands and extending from the Atlantic Ocean tens of kilometers inland. The cold Benguela current upwelling interacts with warm onshore southerly winds in summer causing coastal fogs in this region. We hypothesized that fog and other forms of occult precipitation contribute moisture and nutrients to the vegetation. We measured occult precipitation over one year along a transect running inland in the direction of the prevailing wind and compared the nutrient concentrations with those in rainwater. Occult deposition rates of P, N, K, Mg, Ca, Na, Al and Fe all decreased with distance from the ocean. Furthermore, ratios of cations to Na were similar to those of seawater, suggesting a marine origin for these. In contrast, N and P ratios in occult precipitation were higher than in seawater. We speculate that this is due to marine foam contributing to occult precipitation. Nutrient loss in leaf litter from dominant shrub species was measured to indicate nutrient demand. We estimated that occult precipitation could meet the demand of the dominant shrubby species for annual N, P, K and Ca. Of these species, those with small leaves intercepted more moisture and nutrients than those with larger leaves and could take up foliar deposits of glycine, NO3(-, NH4(+ and Li (as tracer for K through leaf surfaces. We conclude that occult deposition together with rainfall deposition are potentially important nutrient and moisture sources for the Strandveld vegetation that contribute to this vegetation being floristically distinct from neighbouring nutrient-poor Fynbos vegetation.

  20. Does diet influence consumer nutrient cycling? Macroinvertebrate and fish excretion in streams

    Science.gov (United States)

    Ryan McManamay; Jackson Webster; H. Valett; C. Dolloff

    2011-01-01

    Consumer nutrient cycling supplies limiting elements to autotrophic and heterotrophic organisms in aquatic systems. However, the role of consumers in supplying nutrients may change depending on their diet and their own stoichiometry. We evaluated the stoichiometry, N and P excretion, and diets of the dominant macroinvertebrates and fish at 6 stream sites to determine...

  1. Nutrient cycling in primary, secondary forests and cocoa plantation ...

    African Journals Online (AJOL)

    Less leaf litter production and high rainfall regimes in South America and southeast Asia probably contributed to the lower annual nutrient fluxes recorded than that of the dry semi-deciduous tropical forest in Ghana. The soil under cocoa plantation was higher in Ca than in the secondary and primary forests soils.

  2. Closing the water and nutrient cycles in soilless cultivation systems

    NARCIS (Netherlands)

    Beerling, E.A.M.; Blok, C.; Maas, van der A.A.; Os, van E.A.

    2014-01-01

    Soilless cultivation systems are common in Dutch greenhouse horticulture, i.e., less than 20% of the greenhouse area is still soil grown. For long, it was assumed that in these so-called closed systems the emission of nutrients and plant protection products (PPPs) was close to zero. However, Water

  3. Neutral detergent fibre in piglet diets: digestibility, performance, and deposition of body nutrients

    Directory of Open Access Journals (Sweden)

    RAFAEL C. NEPOMUCENO

    2017-12-01

    Full Text Available ABSTRACT A total 120 piglets with an average live weight of 7.00 kg, weaned at 21 days, were used to evaluate the effect of neutral detergent fibre levels on the digestibility of nutrients and energy from the diets, productive performance, and the composition and rate of deposition of nutrients and energy in the bodies of piglets in the nursery phase. The animals were distributed according to a randomized-block design into five treatments, which consisted of neutral detergent fibre levels, with six replicates and four animals per plot. A quadratic effect was detected for the digestibility coefficients of nutrients and energy, feed intake and weight gain. The increase in fibre level promoted a linear increase in fat content in the carcass, blood, and body, whereas the energy in the carcass, organs, and body showed an inverse response. The results showed a quadratic effect on the nutrient deposition rate in the carcass, organs and body. In conclusion, the best digestibility of nutrients and energy from the diet is obtained with 10-11.5% neutral detergent fibre, as higher weight gain and greater protein deposition in the body are achieved at neutral detergent fibre levels of 10.6% and 10.3%, respectively.

  4. Nutrient cycling in a strongly acidified mesotrophic lake

    Czech Academy of Sciences Publication Activity Database

    Kopáček, Jiří; Brzáková, Martina; Hejzlar, Josef; Nedoma, Jiří; Porcal, Petr; Vrba, Jaroslav

    2004-01-01

    Roč. 49, č. 4 (2004), s. 1202-1213 ISSN 0024-3590 R&D Projects: GA ČR(CZ) GA206/00/0063; GA ČR(CZ) GA206/03/1583 Institutional research plan: CEZ:AV0Z6017912 Keywords : acidification * nutrients * water chemistry Subject RIV: DA - Hydrology ; Limnology Impact factor: 3.024, year: 2004

  5. Wetland development, permafrost history and nutrient cycling inferred from late Holocene peat and lake sediment records in subarctic Sweden

    DEFF Research Database (Denmark)

    Kokfelt, U.; Reuss, N.; Struyf, E.

    2010-01-01

    -induced changes in hydrology may further have affected the inflow of alkaline water from the catchment. Elevated contents of biogenic silica and diatom pigments in lake sediments during periods of poor fen and bog expansion further indicate that terrestrial vegetation influenced the amount of nutrients entering...... Sweden to address the late Holocene (5,000 cal BP-present) development of the mire as well as related changes in carbon and nutrient cycling. Formation, sediment accumulation and biogeochemistry of two studied lakes are suggested to be largely controlled by the development of the mire and its permafrost...... to re-deposition of peat into one of the lakes after ca. 2,100 cal BP, and stimulated primary productivity in the other lake at ca. 1,900-1,800 cal BP. Carbonate precipitation appears to have been suppressed when acidic poor fen and bog (palsa) communities dominated the catchment mire, and permafrost...

  6. Nutrient cycling in salt marshes: An ecosystem service to reduce eutrophication

    DEFF Research Database (Denmark)

    Lillebø, A. I.; Sousa, A. I.; Flindt, M. R.

    2013-01-01

    aims to draw attention to the sequestration capacity of salt marshes for the excess of nutrients, and to evaluate the ecological services provided by salt marsh halophytes by regulating the biogeochemical cycles of nitrogen (N) and phosphorus (P). In this context, two case studies will be presented...... and sequestration in salt marshes. This chapter will thus emphasise that salt marsh halophytes have a crucial role on nutrient cycling and sequestration, providing ecological services that contribute to maintain the ecosystem health. © 2012 Nova Science Publishers, Inc. All rights reserved....... and discussed: By comparing young and mature marshes colonised by Saprtina maritima, we will evaluate their behaviour as sink or source of nutrients; By comparing two halophytes with distinct life cycles (Spartina maritima and Scirpus maritimus), we will evaluate species-specific N and P cycling...

  7. Cretaceous paleogeography and depositional cycles of western South America

    Science.gov (United States)

    Macellari, C. E.

    The western margin of South America was encroached upon by a series of marine advances that increased in extent from the Early Cretaceous to a maximum in the early Late Cretaceous for northern South America (Venezuela to Peru). In southern South America, however, the area covered by the marine advances decreased from a maximum in the Early Cretaceous to a minimum during mid-Cretaceous time, followed by a widespread advance at the end of the period. A series of unconformity-bounded depositional cycles was recognized in these sequences: five cycles in northern South America, and six (but not exactly equivalent) cycles in the Cretaceous back-arc basins of southern South America (Neuquén and Austral, or Magallanes, Basins). Both widespread anoxic facies and maximum flooding of the continent in northern South America coincide in general terms with recognized global trends, but this is not the case in southern South America. Here, anoxic facies are restricted to the Lower Cretaceous and seem to be controlled by local aspects of the basin evolution and configuration. The contrasts observed between northern and southern South America can be explained by differences in tectonic setting and evolution. To the north, sediments were deposited around the tectonically stable Guayana-Brazilian Massifs, and thus registered global "signals" such as anoxic events and major eustatic changes. The southern portion of the continent, on the contrary, developed in an active tectonic setting. Here, the mid-Cretaceous Peruvian Orogeny overprinted, to a large extent, world-wide trends and only the earliest and latest Cretaceous conform to global depositional patterns.

  8. Reindeer grazing and soil nutrient cycling in boreal and tundra ecosystems

    OpenAIRE

    Stark, S. (Sari)

    2002-01-01

    Abstract In northernmost Fennoscandia, grazing by reindeer (Rangifer tarandus L.) has a substantial impact on the vegetation of boreal forests and arctic-alpine tundra heaths, which are reflected in below-ground processes, such as nutrient mineralization and soil organic matter decomposition. In the present thesis, the effects of reindeer grazing on soil nutrient cycling were studied by comparing grazed situation with an ungrazed control area in ten boreal forests a...

  9. Atmospheric deposition of nutrients to north Florida rivers: A multivariate statistical analysis. Final report. Master's thesis

    International Nuclear Information System (INIS)

    Fu, J.

    1991-01-01

    Atmospheric nutrient input to the Apalachicola Bay estuary was studied because it has been demonstrated that atmospheric deposition can be a major source of nutrients to eastern U.S. estuaries. Besides the Apalachicola River, the Sopchoppy and the Ochlockonee were also selected for a comparative analysis. Receptor model, absolute principal of component analysis (APCA), and mass balance methods were applied in the study. The results of the study show that nitrogen is probably not a limiting nutrient in the three rivers because their N:P mole ratios are nearly 3 times higher than the Redfield ratio for photosynthesis. The total atmospheric nitrogen depositions in the three river watershed are at least as great as their river fluxes. In the Apalachicola River, the atmospheric source of nitrogen is found to be several times higher than the largest possible input of urban sewage. Atmospheric deposition, therefore, might be the dominant nitrogen source entering the estuary. The results of APCA show that Apalachicola River water is mainly a mixture of components that correspond in their compositions to aged rain, ground water, and fresh rain. Atmospheric nitrate deposition is the result of the air pollution, i.e., acid rain. The studies also show that the annual average deposition of nitrate has a narrow range, mainly from 5.8 to 11.5 kg/ha/yr in most of the NADP sites in the 8 southeastern states. Since all the software and data sets employed in the study are accessible nationwide, the methods could be applied in other watersheds

  10. Biogeochemical Cycling of Nutrients and Trace Metals in the Sediment of Haringvliet Lake: Response to Salinization

    NARCIS (Netherlands)

    Canavan, R.W.

    2006-01-01

    This thesis examines sediment redox processes associated with organic matter degradation and their impact on the cycling of nutrients (N, P) and trace metals (Cd, Co, Ni, Pb, Zn). Our study site, Haringvliet Lake, is located in the Rhine-Meuse River Delta in the southwest of The Netherlands. This

  11. The Influence of Epiphytic Lichens on the Nutrient Cycling of a Blue Oak Woodland

    Science.gov (United States)

    Johannes M. Knops; Thomas H. H. Nash III; William H. Schlesinger

    1997-01-01

    We evaluated the importance of epiphytic lichens in the nutrient cycling of a blue oak (Quercus douglasii) woodland in California. Each oak tree contained an average of 3.8 kg lichen biomass, totaling 590 kg per ha. For comparison, oak leaf biomass was 958 kg per ha. We compared tree growth, volume and composition of throughfall (rainfall falling...

  12. Bivalve grazing, nutrient cycling and phytoplankton dynamics in an estuarine ecosystem

    NARCIS (Netherlands)

    Prins, T.C.

    1996-01-01


    This thesis has considered the impact of the suspension feeding bivalve Mytilusedulis on nutrient cycling and phytoplankton in an estuarine ecosystem. The research was started within the framework of an extensive research project with the

  13. Interactions between plant growth and soil nutrient cycling under elevated CO2: a meta-analysis

    NARCIS (Netherlands)

    Graaff, de M.A.; Groenigen, van K.J.; Six, J.; Hungate, B.; Kessel, van C.

    2006-01-01

    free air carbon dioxide enrichment (FACE) and open top chamber (OTC) studies are valuable tools for evaluating the impact of elevated atmospheric CO2 on nutrient cycling in terrestrial ecosystems. Using meta-analytic techniques, we summarized the results of 117 studies on plant biomass production,

  14. Effects of Fallow Genealogical Cycles on the Build-up of Nutrients in ...

    African Journals Online (AJOL)

    The study examined the effect of fallow generational cycles on the buildup of nutrients in the soil. Fallow sequence of 1st, 2nd, 3rd, 4th and 5th generations were studied. The quadrat approach of sampling was employed to collect soil samples (surface and subsurface) from five plots of 10m x 10m across the five fallow ...

  15. Cars, Cows, and Checkerspot Butterflies: Nitrogen Deposition and Management of Nutrient-Poor Grasslands for a Threatened Species

    OpenAIRE

    Weiss, Stuart B.

    1999-01-01

    Nutrient-poor, serpentinitic soils in the San Francisco Bay area sustain a native grassland that supports many rare species, including the Bay checkerspot butterfly ( Euphydryas editha bayensis). Nitrogen (N) deposition from air pollution threatens biodiversity in these grasslands because N is the primary limiting nutrient for plant growth on serpentinitic soils. I investigated the role of N deposition through surveys of butterfly and plant populations across different grazing regimes, by lit...

  16. Differential effects of canopy trimming and litter deposition on litterfall and nutrient dynamics in a wet subtropical forest

    Science.gov (United States)

    W.L. Silver; S.J. Hall; Grizelle Gonzalez

    2014-01-01

    Humid tropical forests have the highest rates of litterfall production globally, which fuels rapid nutrient recycling and high net ecosystem production. Severe storm events significantly alter patterns in litterfall mass and nutrient dynamics through a combination of canopy disturbance and litter deposition. In this study, we used a large-scale long-term manipulation...

  17. Aluminum sulfate (alum) application interactions with coupled metal and nutrient cycling in a hypereutrophic lake ecosystem.

    Science.gov (United States)

    Nogaro, Geraldine; Burgin, Amy J; Schoepfer, Valerie A; Konkler, Matthew J; Bowman, Katlin L; Hammerschmidt, Chad R

    2013-05-01

    Many lake ecosystems worldwide experience severe eutrophication and associated harmful blooms of cyanobacteria due to high loadings of phosphorus (P). While aluminum sulfate (alum) has been used for decades as chemical treatment of eutrophic waters, the ecological effects of alum on coupled metal and nutrient cycling are not well known. The objective of our study was to investigate the effects of an in-situ alum treatment on aluminum and nutrient (P, N, and S) cycling in a hypereutrophic lake ecosystem. Our results indicate that the addition of alum along with sodium aluminate (as a buffer) increased dissolved aluminum and sulfate in the surface and pore waters, and altered nitrogen cycling by increasing nitrous oxide (N2O) concentrations in the surface water. The increase of aluminum and sulfate may potentially feedback to alter benthic community dynamics. These results enhance our understanding of the unintended ecological consequences of alum treatments in hypereutrophic freshwater ecosystems. Copyright © 2013 Elsevier Ltd. All rights reserved.

  18. Effects of changes in nutrient loading and composition on hypoxia dynamics and internal nutrient cycling of a stratified coastal lagoon

    Science.gov (United States)

    Zhu, Yafei; McCowan, Andrew; Cook, Perran L. M.

    2017-10-01

    The effects of changes in catchment nutrient loading and composition on the phytoplankton dynamics, development of hypoxia and internal nutrient dynamics in a stratified coastal lagoon system (the Gippsland Lakes) were investigated using a 3-D coupled hydrodynamic biogeochemical water quality model. The study showed that primary production was equally sensitive to changed dissolved inorganic and particulate organic nitrogen loads, highlighting the need for a better understanding of particulate organic matter bioavailability. Stratification and sediment carbon enrichment were the main drivers for the hypoxia and subsequent sediment phosphorus release in Lake King. High primary production stimulated by large nitrogen loading brought on by a winter flood contributed almost all the sediment carbon deposition (as opposed to catchment loads), which was ultimately responsible for summer bottom-water hypoxia. Interestingly, internal recycling of phosphorus was more sensitive to changed nitrogen loads than total phosphorus loads, highlighting the potential importance of nitrogen loads exerting a control over systems that become phosphorus limited (such as during summer nitrogen-fixing blooms of cyanobacteria). Therefore, the current study highlighted the need to reduce both total nitrogen and total phosphorus for water quality improvement in estuarine systems.

  19. Effects of changes in nutrient loading and composition on hypoxia dynamics and internal nutrient cycling of a stratified coastal lagoon

    Directory of Open Access Journals (Sweden)

    Y. Zhu

    2017-10-01

    Full Text Available The effects of changes in catchment nutrient loading and composition on the phytoplankton dynamics, development of hypoxia and internal nutrient dynamics in a stratified coastal lagoon system (the Gippsland Lakes were investigated using a 3-D coupled hydrodynamic biogeochemical water quality model. The study showed that primary production was equally sensitive to changed dissolved inorganic and particulate organic nitrogen loads, highlighting the need for a better understanding of particulate organic matter bioavailability. Stratification and sediment carbon enrichment were the main drivers for the hypoxia and subsequent sediment phosphorus release in Lake King. High primary production stimulated by large nitrogen loading brought on by a winter flood contributed almost all the sediment carbon deposition (as opposed to catchment loads, which was ultimately responsible for summer bottom-water hypoxia. Interestingly, internal recycling of phosphorus was more sensitive to changed nitrogen loads than total phosphorus loads, highlighting the potential importance of nitrogen loads exerting a control over systems that become phosphorus limited (such as during summer nitrogen-fixing blooms of cyanobacteria. Therefore, the current study highlighted the need to reduce both total nitrogen and total phosphorus for water quality improvement in estuarine systems.

  20. Evaluating the Contributions of Atmospheric Deposition of Carbon and Other Nutrients to Nitrification in Alpine Environments

    Science.gov (United States)

    Oldani, K. M.; Mladenov, N.; Williams, M. W.

    2013-12-01

    The Colorado Front Range of the Rocky Mountains contains undeveloped, barren soils, yet in this environment there is strong evidence for a microbial role in increased nitrogen (N) export. Barren soils in alpine environments are severely carbon-limited, which is the main energy source for microbial activity and sustenance of life. It has been shown that atmospheric deposition can contain high amounts of organic carbon (C). Atmospheric pollutants, dust events, and biological aerosols, such as bacteria, may be important contributors to the atmospheric organic C load. In this stage of the research we evaluated seasonal trends in the chemical composition and optical spectroscopic (fluorescence and UV-vis absorbance) signatures of snow, wet deposition, and dry deposition in an alpine environment at Niwot Ridge in the Rocky Mountains of Colorado to obtain a better understanding of the sources and chemical character of atmospheric deposition. Our results reveal a positive trend between dissolved organic carbon concentrations and calcium, nitrate and sulfate concentrations in wet and dry deposition, which may be derived from such sources as dust and urban air pollution. We also observed the presence of seasonally-variable fluorescent components that may be attributed to fluorescent pigments in bacteria. These results are relevant because atmospheric inputs of carbon and other nutrients may influence nitrification in barren, alpine soils and, ultimately, the export of nitrate to alpine watersheds.

  1. Resuspension and estuarine nutrient cycling: insights from the Neuse River Estuary

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    D. R. Corbett

    2010-10-01

    Full Text Available For at least the past several decades, North Carolina's Neuse River Estuary (NRE has been subject to water quality problems relating to increased eutrophication. Research initiated in the past several years have addressed the nutrient processes of the water column and the passive diffusion processes of the benthic sedimentary environment. Resuspension of bottom sediments, by bioturbation, tides, or winds, may also have a significant effect on the flux of nutrients in an estuarine system These processes can result in the advective transport of sediment porewater, rich with nitrogen, phosphorus and carbon, into the water column. Thus, estimates of nutrient and carbon inputs from the sediments may be too low.

    This study focused on the potential change in bottom water nutrient concentrations associated with measured resuspension events. Previous research used short-lived radionuclides and meteorological data to characterize the sediment dynamics of the benthic system of the estuary. These techniques in conjunction with the presented porewater inventories allowed evaluation of the depth to which sediments have been disturbed and the advective flux of nutrients to the water column. The largest removal episode occurred in the lower NRE as the result of a wind event and was estimated that the top 2.2 cm of sediment and corresponding porewater were removed. NH4+ advective flux (resuspended was 2 to 6 times greater than simply diffusion. Phosphate fluxes were estimated to be 15 times greater than the benthic diffusive flux. Bottom water conditions with elevated NH4+ and PO43− indicate that nutrients stored in the sediments continue to play an important role in overall water quality and this study suggests that the advective flux of nutrients to the water column is critical to understand estuarine nutrient cycling.

  2. Exogenous nutrients and carbon resource change the responses of soil organic matter decomposition and nitrogen immobilization to nitrogen deposition.

    Science.gov (United States)

    He, Ping; Wan, Song-Ze; Fang, Xiang-Min; Wang, Fang-Chao; Chen, Fu-Sheng

    2016-03-29

    It is unclear whether exogenous nutrients and carbon (C) additions alter substrate immobilization to deposited nitrogen (N) during decomposition. In this study, we used laboratory microcosm experiments and (15)N isotope tracer techniques with five different treatments including N addition, N+non-N nutrients addition, N+C addition, N+non-N nutrients+C addition and control, to investigate the coupling effects of non-N nutrients, C addition and N deposition on forest floor decomposition in subtropical China. The results indicated that N deposition inhibited soil organic matter and litter decomposition by 66% and 38%, respectively. Soil immobilized (15)N following N addition was lowest among treatments. Litter (15)N immobilized following N addition was significantly higher and lower than that of combined treatments during the early and late decomposition stage, respectively. Both soil and litter extractable mineral N were lower in combined treatments than in N addition treatment. Since soil N immobilization and litter N release were respectively enhanced and inhibited with elevated non-N nutrient and C resources, it can be speculated that the N leaching due to N deposition decreases with increasing nutrient and C resources. This study should advance our understanding of how forests responds the elevated N deposition.

  3. Groundwater Availability Alters Soil-plant Nutrient Cycling in a Stand of Invasive, N-fixing Phreatophytes

    Science.gov (United States)

    Dudley, B. D.; Miyazawa, Y.; Hughes, F.; Ostertag, R.; Kettwich, S. K.; MacKenzie, R.; Dulaiova, H.; Waters, C. A.; Bishop, J.; Giambelluca, T. W.

    2013-12-01

    N-fixing phreatophytic trees are common in arid and semi-arid regions worldwide, and can play significant roles in modifying hydrology and soil-plant nutrient cycling where they are present. In light of reductions in groundwater levels in many arid regions we estimated annual transpiration rates at a stand level, and alterations to C, N and P accretion in soils as a function of groundwater depth in a ca.120 year old stand of Prosopis pallida along an elevation gradient in coastal leeward Hawaii. We measured sapflow and stand level sapwood area to quantify transpiration, and calculated groundwater transpiration rates using P. pallida stem water δ18O values. By measuring soil resistivity, we were able to compare the volume of groundwater transpired by these trees to groundwater depth across the stand. We examined nutrient deposition and accretion in soils in lowland areas of the stand with accessible shallow groundwater, compared to upland areas with no groundwater access, as indicated by stem water δ18O values. Resistivity results suggested that groundwater was at a height close to sea level throughout the stand. Transpiration was around 1900 m3 ha-1 year-1 in the areas of the stand closest to the sea (where groundwater was at around 1-4 m below ground level) and decreased to around a tenth of that volume where groundwater was not accessible. Litterfall rates over the course of the year studied were 17 times greater at lowland sites, but this litterfall contributed ca. 24 times the N, and 35 times the P of upland sites. Thus, groundwater access contributed to the total mass of nitrogen and phosphorus deposited in the form of litter through higher litter quantity and quality. Total N content of soils was 4.7 times greater and inorganic N pools were eight times higher at lowland plots. These results suggest that groundwater depth can have strong effects on soil-plant nutrient cycling, so that reductions in the availability of shallow groundwater are likely to impact

  4. Life cycle assessment and nutrient analysis of various processing pathways in algal biofuel production.

    Science.gov (United States)

    Mu, Dongyan; Ruan, Roger; Addy, Min; Mack, Sarah; Chen, Paul; Zhou, Yong

    2017-04-01

    This study focuses on analyzing nutrient distributions and environmental impacts of nutrient recycling, reusing, and discharging in algal biofuels production. The three biomass conversion pathways compared in this study were: hydrothermal liquefaction technology (HTL), hydrothermal hydrolysis pretreatment +HTL (HTP), and wet lipid extraction (WLE). Carbon, nitrogen, and phosphorous (C, N, P) flows were described in each pathway. A primary cost analysis was conducted to evaluate the economic performance. The LCA results show that the HTP reduced life cycle NO x emissions by 10% from HTL, but increased fossil fuel use, greenhouse gas emissions, and eutrophication potential by 14%, 5%, and 28% respectively. The cost of per gallon biodiesel produced in HTP was less than in HTL. To further reduce emissions, efforts should be focused on improving nutrient uptake rates in algae cultivation, increasing biomass carbon detention in hydrothermal hydrolysis, and/or enhancing biomass conversion rates in the biooil upgrading processes. Copyright © 2017 Elsevier Ltd. All rights reserved.

  5. Ecosystem Service of Shade Trees on Nutrient Cycling and Productivity of Coffee Agro-ecosystems

    OpenAIRE

    Rusdi Evizal; Tohari Tohari; Irfan D. Prijambada; Jaka Widada; Donny Widianto

    2009-01-01

    Shade trees are significant in certification scheme of sustainable coffee production. They play an importance role on ecosystem functioning. This research is aimed to study ecosystem service of shade trees in some coffee agro-ecosystems particularly on nutrient cycling and land productivity. Four agro-ecosys tems of Robusta coffee (Coffea canephora), namely sun coffee (without shade trees), coffee shaded by Michelia champaca, coffee shaded by Gliricidia sepium, and coffee shaded by Erythrina ...

  6. Ecosystem Service of Shade Trees on Nutrient Cycling and Productivity of Coffee Agro-ecosystems

    Directory of Open Access Journals (Sweden)

    Rusdi Evizal

    2009-05-01

    Full Text Available Shade trees are significant in certification scheme of sustainable coffee production. They play an importance role on ecosystem functioning. This research is aimed to study ecosystem service of shade trees in some coffee agro-ecosystems particularly on nutrient cycling and land productivity. Four agro-ecosys tems of Robusta coffee (Coffea canephora, namely sun coffee (without shade trees, coffee shaded by Michelia champaca, coffee shaded by Gliricidia sepium, and coffee shaded by Erythrina indica are evaluated during 2007—2008. Smallholder coffee plantation in Sumberjaya Subdistrict, West Lampung, which managed under local standard were employed using Randomized Complete Block Design with 3 replications. The result showed that litter fall dynamic from shade trees and from coffee trees was influenced by rainfall. Shade trees decreased weed biomass while increased litter fall production. In dry season, shade trees decreased litter fall from coffee shaded by M. champaca. G. sepium and E. indica shaded coffee showed higher yield than sun coffee and M. champaca shaded coffee. Except for M. champaca shaded coffee, yield had positive correlation (r = 0.99 with litter fall production and had negative correlation (r = —0.82 with weed biomass production. Biomass production (litter fall + weed of sun coffee and shaded coffee was not significantly different. Litter fall of shade trees had significance on nutrient cycle mainly to balance the lost of nitrogen in coffee bean harvesting.Key Words: Coffea canephora, Michelia champaca, Gliricidia sepium, Erythrina indica, litter production, nutrient cycle, coffee yield.

  7. The microbial perspective of organic matter turnover and nutrient cycling in tropical soils

    Science.gov (United States)

    Rasche, Frank

    2017-04-01

    A primary goal of low-input small-holder farming systems in the tropics is the appropriate management of organic matter (OM) turnover and nutrient cycling via adapted agricultural practices. These emphasize the promotion of soil organic matter (SOM) turnover and carbon (C) sequestration, nutrient use efficiency and soil microbial activity. Since soil microbial communities are acknowledged as key players in the terrestrial C and nutrient (e.g., nitrogen (N), phosphorus (P)) cycles, they may respond sensitively to agricultural management with shifts in their community structure as well as functional traits (i.e., decomposition, mineralization). This may be in particular evident for tropical, agricultural soils which show an accelerated microbial decomposition activity induced by favourable climatic and unique physico-chemical soil conditions. While modern molecular techniques advanced primarily the understanding about the microbiome and their functional traits interacting closely with SOM dynamics in temperate soils, tropical soils under agricultural use have been still neglected to a great extent. The majority of available studies revealed mainly descriptive data on the structural composition of microbial communities rather than questioning if detected structural alterations of the soil microbiome influenced key processes in N and P cycling which actually maintain ecosystem functioning and soil productivity. This talk highlights latest efforts in deploying molecular techniques to study the compositional status of soil microbial decomposer communities and their functional attributes in response to land use change and OM management in tropical agro-ecosystems.

  8. Coupled nutrient cycling determines tropical forest trajectory under elevated CO2.

    Science.gov (United States)

    Bouskill, N.; Zhu, Q.; Riley, W. J.

    2017-12-01

    Tropical forests have a disproportionate capacity to affect Earth's climate relative to their areal extent. Despite covering just 12 % of land surface, tropical forests account for 35 % of global net primary productivity and are among the most significant of terrestrial carbon stores. As atmospheric CO2 concentrations increase over the next century, the capacity of tropical forests to assimilate and sequester anthropogenic CO2 depends on limitation by multiple factors, including the availability of soil nutrients. Phosphorus availability has been considered to be the primary factor limiting metabolic processes within tropical forests. However, recent evidence points towards strong spatial and temporal co-limitation of tropical forests by both nitrogen and phosphorus. Here, we use the Accelerated Climate Modeling for Energy (ACME) Land Model (ALMv1-ECA-CNP) to examine how nutrient cycles interact and affect the trajectory of the tropical forest carbon sink under, (i) external nutrient input, (ii) climate (iii) elevated CO2, and (iv) a combination of 1-3. ALMv1 includes recent theoretical advances in representing belowground competition between roots, microbes and minerals for N and P uptake, explicit interactions between the nitrogen and phosphorus cycles (e.g., phosphatase production and nitrogen fixation), the dynamic internal allocation of plant N and P resources, and the integration of global datasets of plant physiological traits. We report nutrient fertilization (N, P, N+P) predictions for four sites in the tropics (El Verde, Puerto Rico, Barro Colorado Island, Panama, Manaus, Brazil and the Osa Peninsula, Coast Rica) to short-term nutrient fertilization (N, P, N+P), and benchmarking of the model against a meta-analysis of forest fertilization experiments. Subsequent simulations focus on the interaction of the carbon, nitrogen, and phosphorus cycles across the tropics with a focus on the implications of coupled nutrient cycling and the fate of the tropical

  9. Dimensions of biodiversity of oceanic nitrogen cycling: nutrient co-limitation, nitrogen substrate preferences and more.

    Science.gov (United States)

    Zehr, J.; Mills, M. M.; Shilova, I. N.; Turk-Kubo, K.; Robidart, J.; van Dijken, G.; Bjorkman, K. M.; Whitt, D. B.; Wai, B.; Pampin Baro, J.; Hogan, M.; Rapp, I.; Zakem, E.; Fredrickson, A.; Leahy, B.; Linney, M.; Santiago, A.; Follows, M. J.; Achterberg, E. P.; Kolber, Z.; Church, M. J.; Arrigo, K. R.

    2016-02-01

    We conducted the research cruise: Nutrient Effects on Marine microOrganisms (NEMO) onboard the R/V New Horizon (NH1417: August 18 to September 16, 2014) between the ports of San Diego, CA and Honolulu, HI. The three major objectives of the cruise were to: 1) evaluate genetic, physiological and phylogenetic responses of marine phytoplankton communities in the North Pacific Subtropical Gyre to different nitrogen (N) substrates and to determine how other nutrients (iron, phosphorus) impact N utilization; 2) characterize the physical processes and dynamics in support of the biological processes; and 3) characterize the diversity and activities of microbial communities in the upper water column in relation to the nutrient availability. Several incubation experiments were conducted along the cruise transect to assess the effect of nutrients on microbial communities. The results showed that N addition resulted in increased chlorophyll a (chl a) and rates of CO2 fixation at most sites, but Prochlorococcus, Synechococcus and picoekaryotic phytoplankton had different responses to urea, ammonium and nitrate. In contrast, chl a and CO2 fixation did not respond to additions of single nutrient (e.g. N, P or Fe alone) at the westernmost experiment (151°W), where the simultaneous addition of N and P was required for stimulation. The physical dynamics were studied through high-resolution surveys of eddy dipole features as well as diel sampling at two locations. Additionally, we characterized an extensive bloom that occurred near the critical latitude (29°N, 140°W) from mid July to the end of September; a typical but still enigmatic event. Here, we present a summary of the initial observations and findings from the NEMO cruise with data including physics, nutrient concentrations, chl a, primary productivity and microbial community composition. The results of this research cruise will help in assessing how ocean N cycling and ecosystem functions will respond to global climate

  10. Applying Sewage Sludge to Eucalyptus grandis Plantations: Effects on Biomass Production and Nutrient Cycling through Litterfall

    International Nuclear Information System (INIS)

    Da Silva, P.H.M.; Poggiani, F.; Laclau, J.P.

    2011-01-01

    In most Brazilian cities sewage sludge is dumped into sanitary landfills, even though its use in forest plantations as a fertilizer and soil conditioner might be an interesting option. Sewage sludge applications might reduce the amounts of mineral fertilizers needed to sustain the productivity on infertile tropical soils. However, sewage sludge must be applied with care to crops to avoid soil and water pollution. The aim of our study was to assess the effects of dry and wet sewage sludges on the growth and nutrient cycling of Eucalyptus grandis plantations established on the most common soil type for Brazilian eucalypt plantations. Biomass production and nutrient cycling were studied over a 36-month period in a complete randomized block design. Four experimental treatments were compared: wet sewage sludge, dry sludge, mineral fertilizer, and no fertilizer applications. The two types of sludges as well as mineral fertilizer increased significantly the biomass of Eucalyptus trees. Wood biomass productions 36 months after planting were similar in the sewage sludge and mineral fertilization treatments (about 80 tons ha - '1) and 86 % higher than in the control treatment. Sewage sludge application also affected positively leaf litter production and significantly increased nutrient transfer among the components of the ecosystem.

  11. Applying Sewage Sludge to Eucalyptus grandis Plantations: Effects on Biomass Production and Nutrient Cycling through Litterfall

    Directory of Open Access Journals (Sweden)

    Paulo Henrique Müller da Silva

    2011-01-01

    Full Text Available In most Brazilian cities sewage sludge is dumped into sanitary landfills, even though its use in forest plantations as a fertilizer and soil conditioner might be an interesting option. Sewage sludge applications might reduce the amounts of mineral fertilizers needed to sustain the productivity on infertile tropical soils. However, sewage sludge must be applied with care to crops to avoid soil and water pollution. The aim of our study was to assess the effects of dry and wet sewage sludges on the growth and nutrient cycling of Eucalyptus grandis plantations established on the most common soil type for Brazilian eucalypt plantations. Biomass production and nutrient cycling were studied over a 36-month period in a complete randomized block design. Four experimental treatments were compared: wet sewage sludge, dry sludge, mineral fertilizer, and no fertilizer applications. The two types of sludges as well as mineral fertilizer increased significantly the biomass of Eucalyptus trees. Wood biomass productions 36 months after planting were similar in the sewage sludge and mineral fertilization treatments (about 80 tons ha−1 and 86% higher than in the control treatment. Sewage sludge application also affected positively leaf litter production and significantly increased nutrient transfer among the components of the ecosystem.

  12. The biogeochemical role of baleen whales and krill in Southern Ocean nutrient cycling.

    Directory of Open Access Journals (Sweden)

    Lavenia Ratnarajah

    Full Text Available The availability of micronutrients is a key factor that affects primary productivity in High Nutrient Low Chlorophyll (HNLC regions of the Southern Ocean. Nutrient supply is governed by a range of physical, chemical and biological processes, and there are significant feedbacks within the ecosystem. It has been suggested that baleen whales form a crucial part of biogeochemical cycling processes through the consumption of nutrient-rich krill and subsequent defecation, but data on their contribution are scarce. We analysed the concentration of iron, cadmium, manganese, cobalt, copper, zinc, phosphorus and carbon in baleen whale faeces and muscle, and krill tissue using inductively coupled plasma mass spectrometry. Metal concentrations in krill tissue were between 20 thousand and 4.8 million times higher than typical Southern Ocean HNLC seawater concentrations, while whale faecal matter was between 276 thousand and 10 million times higher. These findings suggest that krill act as a mechanism for concentrating and retaining elements in the surface layer, which are subsequently released back into the ocean, once eaten by whales, through defecation. Trace metal to carbon ratios were also higher in whale faeces compared to whale muscle indicating that whales are concentrating carbon and actively defecating trace elements. Consequently, recovery of the great whales may facilitate the recycling of nutrients via defecation, which may affect productivity in HNLC areas.

  13. The biogeochemical role of baleen whales and krill in Southern Ocean nutrient cycling.

    Science.gov (United States)

    Ratnarajah, Lavenia; Bowie, Andrew R; Lannuzel, Delphine; Meiners, Klaus M; Nicol, Stephen

    2014-01-01

    The availability of micronutrients is a key factor that affects primary productivity in High Nutrient Low Chlorophyll (HNLC) regions of the Southern Ocean. Nutrient supply is governed by a range of physical, chemical and biological processes, and there are significant feedbacks within the ecosystem. It has been suggested that baleen whales form a crucial part of biogeochemical cycling processes through the consumption of nutrient-rich krill and subsequent defecation, but data on their contribution are scarce. We analysed the concentration of iron, cadmium, manganese, cobalt, copper, zinc, phosphorus and carbon in baleen whale faeces and muscle, and krill tissue using inductively coupled plasma mass spectrometry. Metal concentrations in krill tissue were between 20 thousand and 4.8 million times higher than typical Southern Ocean HNLC seawater concentrations, while whale faecal matter was between 276 thousand and 10 million times higher. These findings suggest that krill act as a mechanism for concentrating and retaining elements in the surface layer, which are subsequently released back into the ocean, once eaten by whales, through defecation. Trace metal to carbon ratios were also higher in whale faeces compared to whale muscle indicating that whales are concentrating carbon and actively defecating trace elements. Consequently, recovery of the great whales may facilitate the recycling of nutrients via defecation, which may affect productivity in HNLC areas.

  14. Quantifying nutrient export and deposition with a dynamic landscape evolution model for the lake Bolsena watershed, Italy

    Science.gov (United States)

    Pelorosso, Raffaele; Temme, Arnoud; Gobattoni, Federica; Leone, Antonio

    2010-05-01

    Excessive nutrient loads from upstream watershed activities such as agriculture, hydrological modifications, and urban runoff, have been identified as the leading cause of deterioration in assessed lakes and reservoirs (USEPA, 2000; Leone et al., 2001; Leone et al., 2003). Excessive nutrient transport into lakes and reservoirs may accelerate eutrophication rates, causing negative impacts on aesthetic and water quality. As reservoirs become eutrophic, they are depleted in oxygen and enriched in suspended solids, with heavy consequences for ecosystems and natural habitats. Management of nutrient loads into reservoirs requires knowledge of nutrient transport and delivery from the watershed-stream system (Ripa, 2003). Managing uncultivated lands in watersheds may be a cost effective way to improve water quality in agricultural landscapes, and recent advances in landscape ecology highlight important relationships between the structural configuration of these lands and nutrient redistribution (e.g., Forman 1987; Barrett and others 1990). Many studies have been carried out to underline and explain how landscape characteristics and structure may affect these processes. In these studies, relations between land cover and nutrient storage were analyzed using geographic information systems (GIS) (e.g. Lucas, 2002). Nutrients are generally transported from the landscape into streams during runoff events; however, they may also enter stream flow from other sources such as groundwater recharge and point source effluent discharges (Lucas, 2002; Nielsen, 2007; Waldron, 2008; Castillo, 2009). Water moves nutrients and delivers them to downstream water bodies such as lakes and reservoirs so that erosion phenomena play an essential role in determining nutrients fluxes and deposition. On the one hand, several hydrological models take into account nutrients reactions, movements and deposition - coupling soil erosion processes with transport equations (Bartley, 2004; Lű, 2010). On the

  15. Environmental performance of biological nutrient removal processes from a life cycle perspective.

    Science.gov (United States)

    Ontiveros, Guillermo A; Campanella, Enrique A

    2013-12-01

    The goal of the present study is to assess different alternatives for a wastewater treatment plant module with capacity to remove nutrients biologically, taking into account present Argentine regulations for effluent discharge. A computational modeling tool (GPS-X) was employed to simulate the behavior of the different alternatives, and Life Cycle Assessment was applied to quantify the environmental impact. A 2000 m(3)/d municipal wastewater flow was used to carry out the simulations, the annual flow was utilized as functional units and the main topics analyzed were energy efficiency, land use, eutrophication reduction and biosolid reuse. Biogas and biosolid generation was evaluated as a good opportunity to generate a cleaner process. This study highlights the fact that nutrient removal processes significantly improve the quality of effluent and biosolids and reduces energy consumption. Copyright © 2013 Elsevier Ltd. All rights reserved.

  16. Episodic upwelling and dust deposition as bloom triggers in low-nutrient, low-chlorophyll regions

    Science.gov (United States)

    Calil, Paulo H. R.; Doney, Scott C.; Yumimoto, Keiya; Eguchi, Kenta; Takemura, Toshihiko

    2011-06-01

    Summertime phytoplankton blooms in the oligotrophic North Pacific Ocean are supported by N2-fixing organisms that relieve the system of nitrate limitation. Phosphate and iron, however, limit their growth and need to be supplied for these organisms to thrive. We analyze two recent blooms in the region whose differences provide insight into their possible formation mechanisms. In 2008, a typical late summer bloom, with sporadic patches of higher-chlorophyll concentration, occurred near the island chain and the subtropical front. In 2010, an unusually large, contiguous bloom was observed in the western oligotrophic North Pacific, a region where blooms seldom, if ever, occur. Streaks of high chlorophyll in 2008 coincide with surface temperature fronts and regions of large horizontal stretching, as detected by Lagrangian diagnostics. Such regions are prone to the generation of vertical velocities via frontogenesis. Horizontal transport from upwelling regions or iron-rich island sediments is also important for the redistribution of nutrients. In the case of the 2010 bloom, we use a global aerosol transport model as well as space-borne lidar observations to argue that atmospheric dust deposition events prior to the bloom provided the necessary nutrient conditions for the growth of N2-fixing organisms. As sea surface temperature increased in the region, chlorophyll values increased significantly, showing that this bloom was likely a consequence of prior enrichment and that temperature is a key factor in bloom development in this important biome.

  17. A mechanistic soil biogeochemistry model with explicit representation of microbial and macrofaunal activities and nutrient cycles

    Science.gov (United States)

    Fatichi, Simone; Manzoni, Stefano; Or, Dani; Paschalis, Athanasios

    2016-04-01

    The potential of a given ecosystem to store and release carbon is inherently linked to soil biogeochemical processes. These processes are deeply connected to the water, energy, and vegetation dynamics above and belowground. Recently, it has been advocated that a mechanistic representation of soil biogeochemistry require: (i) partitioning of soil organic carbon (SOC) pools according to their functional role; (ii) an explicit representation of microbial dynamics; (iii) coupling of carbon and nutrient cycles. While some of these components have been introduced in specialized models, they have been rarely implemented in terrestrial biosphere models and tested in real cases. In this study, we combine a new soil biogeochemistry model with an existing model of land-surface hydrology and vegetation dynamics (T&C). Specifically the soil biogeochemistry component explicitly separates different litter pools and distinguishes SOC in particulate, dissolved and mineral associated fractions. Extracellular enzymes and microbial pools are explicitly represented differentiating the functional roles of bacteria, saprotrophic and mycorrhizal fungi. Microbial activity depends on temperature, soil moisture and litter or SOC stoichiometry. The activity of macrofauna is also modeled. Nutrient dynamics include the cycles of nitrogen, phosphorous and potassium. The model accounts for feedbacks between nutrient limitations and plant growth as well as for plant stoichiometric flexibility. In turn, litter input is a function of the simulated vegetation dynamics. Root exudation and export to mycorrhiza are computed based on a nutrient uptake cost function. The combined model is tested to reproduce respiration dynamics and nitrogen cycle in few sites where data were available to test plausibility of results across a range of different metrics. For instance in a Swiss grassland ecosystem, fine root, bacteria, fungal and macrofaunal respiration account for 40%, 23%, 33% and 4% of total belowground

  18. Effects of nitrogen deposition on carbon cycle in terrestrial ecosystems of China

    DEFF Research Database (Denmark)

    Chen, Hao; Li, Dejun; Gurmesa, Geshere Abdisa

    2015-01-01

    Nitrogen (N) deposition in China has increased greatly, but the general impact of elevated N deposition on carbon (C) dynamics in Chinese terrestrial ecosystems is not well documented. In this study we used a meta-analysis method to compile 88 studies on the effects of N deposition C cycling...... and rate of N addition. Overall, our findings suggest that 1) decreased below-ground plant C pool may limit long-term soil C sequestration; and 2) it is better to treat N-rich and N-limited ecosystems differently in modeling effects of N deposition on ecosystem C cycle....

  19. Internal cycling, not external loading, decides the nutrient limitation in eutrophic lake: A dynamic model with temporal Bayesian hierarchical inference.

    Science.gov (United States)

    Wu, Zhen; Liu, Yong; Liang, Zhongyao; Wu, Sifeng; Guo, Huaicheng

    2017-06-01

    Lake eutrophication is associated with excessive anthropogenic nutrients (mainly nitrogen (N) and phosphorus (P)) and unobserved internal nutrient cycling. Despite the advances in understanding the role of external loadings, the contribution of internal nutrient cycling is still an open question. A dynamic mass-balance model was developed to simulate and measure the contributions of internal cycling and external loading. It was based on the temporal Bayesian Hierarchical Framework (BHM), where we explored the seasonal patterns in the dynamics of nutrient cycling processes and the limitation of N and P on phytoplankton growth in hyper-eutrophic Lake Dianchi, China. The dynamic patterns of the five state variables (Chla, TP, ammonia, nitrate and organic N) were simulated based on the model. Five parameters (algae growth rate, sediment exchange rate of N and P, nitrification rate and denitrification rate) were estimated based on BHM. The model provided a good fit to observations. Our model results highlighted the role of internal cycling of N and P in Lake Dianchi. The internal cycling processes contributed more than external loading to the N and P changes in the water column. Further insights into the nutrient limitation analysis indicated that the sediment exchange of P determined the P limitation. Allowing for the contribution of denitrification to N removal, N was the more limiting nutrient in most of the time, however, P was the more important nutrient for eutrophication management. For Lake Dianchi, it would not be possible to recover solely by reducing the external watershed nutrient load; the mechanisms of internal cycling should also be considered as an approach to inhibit the release of sediments and to enhance denitrification. Copyright © 2017 Elsevier Ltd. All rights reserved.

  20. Representation of deforestation impacts on climate, water, and nutrient cycles in the ACME earth system model

    Science.gov (United States)

    Cai, X.; Riley, W. J.; Zhu, Q.

    2017-12-01

    Deforestation causes a series of changes to the climate, water, and nutrient cycles. Employing a state-of-the-art earth system model—ACME (Accelerated Climate Modeling for Energy), we comprehensively investigate the impacts of deforestation on these processes. We first assess the performance of the ACME Land Model (ALM) in simulating runoff, evapotranspiration, albedo, and plant productivity at 42 FLUXNET sites. The single column mode of ACME is then used to examine climate effects (temperature cooling/warming) and responses of runoff, evapotranspiration, and nutrient fluxes to deforestation. This approach separates local effects of deforestation from global circulation effects. To better understand the deforestation effects in a global context, we use the coupled (atmosphere, land, and slab ocean) mode of ACME to demonstrate the impacts of deforestation on global climate, water, and nutrient fluxes. Preliminary results showed that the land component of ACME has advantages in simulating these processes and that local deforestation has potentially large impacts on runoff and atmospheric processes.

  1. Influences of Moisture Regimes and Functional Plant Types on Nutrient Cycling in Permafrost Regions

    Science.gov (United States)

    McCaully, R. E.; Arendt, C. A.; Newman, B. D.; Heikoop, J. M.; Wilson, C. J.; Sevanto, S.; Wales, N. A.; Wullschleger, S.

    2017-12-01

    In the permafrost-dominated Arctic, climatic feedbacks exist between permafrost, soil moisture, functional plant type and presence of nutrients. Functional plant types present within the Arctic regulate and respond to changes in hydrologic regimes and nutrient cycling. Specifically, alders are a member of the birch family that use root nodules to fix nitrogen, which is a limiting nutrient strongly linked to fertilizing Arctic ecosystems. Previous investigations in the Seward Peninsula, AK show elevated presence of nitrate within and downslope of alder patches in degraded permafrost systems, with concentrations an order of magnitude greater than that of nitrate measured above these patches. Further observations within these degraded permafrost systems are crucial to assess whether alders are drivers of, or merely respond to, nitrate fluxes. In addition to vegetative feedbacks with nitrate supply, previous studies have also linked low moisture content to high nitrate production. Within discontinuous permafrost regions, the absence of permafrost creates well-drained regions with unsaturated soils whereas the presence of permafrost limits vertical drainage of soil-pore water creating elevated soil moisture content, which likely corresponds to lower nitrate concentrations. We investigate these feedbacks further in the Seward Peninsula, AK, through research supported by the United States Department of Energy Next Generation Ecosystem Experiment (NGEE) - Arctic. Using soil moisture and thaw depth as proxies to determine the extent of permafrost degradation, we identify areas of discontinuous permafrost over a heterogeneous landscape and collect co-located soilwater chemistry samples to highlight the complex relationships that exist between alder patches, soil moisture regimes, the presence of permafrost and available nitrate supply. Understanding the role of nitrogen in degrading permafrost systems, in the context of both vegetation present and soil moisture, is crucial

  2. Nutrient cycling and ecosystem metabolism in boreal streams of the Central Siberian Plateau

    Science.gov (United States)

    Diemer, L.; McDowell, W. H.; Prokushkin, A. S.

    2013-12-01

    mechanisms controlling nutrient processing and productivity in headwater streams of Central Siberia will be critical to understanding global biogeochemical cycling, particularly as these systems respond to climate change.

  3. Nitrogen deposition and cycling across an elevation and vegetation gradient in southern Appalachian forests

    Science.gov (United States)

    Jennifer D. Knoepp; James M. Vose; Wayne T. Swank

    2008-01-01

    We studied nitrogen (N) cycling pools and processes across vegetation and elevation gradients in. the southern Appalachian Mountains in SE USA. Measurements included bulk deposition input, watershed export, throughfall fluxes, litterfall, soil N pools and processes, and soil solution N. N deposition increased with elevation and ranged from 9.5 to 12.4 kg ha-...

  4. Effects of dust deposition on iron cycle in the surface Mediterranean Sea: results from a mesocosm seeding experiment

    Directory of Open Access Journals (Sweden)

    T. Wagener

    2010-11-01

    Full Text Available Soil dust deposition is recognized as a major source of iron to the open ocean at global and regional scales. However, the processes that control the speciation and cycle of iron in the surface ocean after dust deposition are poorly documented mainly due to the logistical difficulties to investigate in-situ, natural dust events. The development of clean mesocosms in the frame of the DUNE project (a DUst experiment in a low Nutrient low chlorophyll Ecosystem was a unique opportunity to investigate these processes at the unexplored scale of one dust deposition event. During the DUNE-1-P mesocosm seeding experiment, iron stocks (dissolved and particulate concentrations in the water column and fluxes (export of particulate iron in sediment traps were followed during 8 days after an artificial dust seeding mimicking a wet deposition of 10 g m−2. The addition of dust at the surface of the mesocosms was immediately followed by a decrease of dissolved iron [dFe] concentration in the 0–10 m water column. This decrease was likely due to dFe scavenging on settling dust particles and mineral organic aggregates. The scavenging ratio of dissolved iron on dust particles averaged 0.37 ± 0.12 nmol mg−1. Batch dissolution experiments conducted in parallel to the mesocosm experiment showed a increase (up to 600% in dust iron dissolution capacity in dust-fertilized waters compared to control conditions. This study gives evidences of complex and unexpected effects of dust deposition on surface ocean biogeochemistry: (1 large dust deposition events may be a sink for surface ocean dissolved iron and (2 successive dust deposition events may induce different biogeochemical responses in the surface ocean.

  5. The smog-fog-smog cycle and acid deposition

    Science.gov (United States)

    Pandis, Spyros N.; Seinfeld, John H.; Pilinis, Christodoulos

    1990-10-01

    A model including descriptions of aerosol and droplet microphysics, gas and aqueous-phase chemistry, and deposition is used to study the transformation of aerosol to fog droplets and back to aerosol in an urban environment. Fogs in polluted environments have the potential to increase aerosol sulfate concentrations but at the same time to cause reductions in the aerosol concentration of nitrate, chloride, ammonium and sodium and well as in the total aerosol mass concentration. The sulfate produced during fog episodes favors the aerosol particles that have access to most of the fog liquid water which are usually the large particles. Aerosol scavenging efficiencies of around 80 percent are calculated for urban fogs. Sampling and subsequent mixing of fog droplets of different sizes may result in measured concentrations that are not fully representative of the fogwater chemical composition and can introduce errors in the reported values of the ionic species deposition velocities. Differences in the major ionic species deposition velocities can be explained by their distribution over the droplet size spectrum and can be correlated with the species average diameter. Two different expressions are derived for use in fog models for the calculation of the liquid water deposition velocity during fog growth and dissipation stages.

  6. Biomass production and nutrient cycling in Eucalyptus short rotation energy forests in New Zealand: II. Litter fall and nutrient return

    Energy Technology Data Exchange (ETDEWEB)

    Guo, L.B.; Sims, R.E.H. [Institute of Technology and Engineering, Massey University, Private Bag 11222, Palmerston North (New Zealand); Horne, D.J. [Institute of Natural Resources, Massey University, Private Bag 11222, Palmerston North (New Zealand)

    2006-05-15

    Litter fall and nutrient return via the litter fall were measured during the first 3-yr rotation of three Eucalyptus short rotation forest species (E. botryoides, E. globulus and E. ovata) irrigated with meatworks effluent compared with no irrigation. Up to 13.4 oven-dry t/ha/yr of annual litter fall was recorded with nutrient returns of up to 159kgN/ha/yr, 9kgP/ha/yr, 28kgK/ha/yr, 125kgCa/ha/yr, 22kgMg/ha/yr, and 32kgMn/ha/yr. Effluent irrigation increased the litter fall and the return of some nutrients. More litter fall with higher nutrient return was found under E. globulus than under the other two species. However, the amounts of litter fall and nutrient return were highly dependent on the degree of biomass production and nutrient uptake. During the 3-yr period, up to 20% of the total above ground biomass produced was in the form of litter, and via the litter fall, up to 24% of the total N uptake was returned to the soil surface. (author)

  7. Calculation of growth per cycle (GPC) of atomic layer deposited ...

    Indian Academy of Sciences (India)

    2014-03-06

    Mar 6, 2014 ... Abstract. In this paper a theoretical calculation is presented for the growth per cycle (GPC) of the film and the variation of GPC with OH concentration on the substrate surface. The calculated GPC range (0.179 nm–0.075 nm) agrees well with reported experimental values. The present approach yielded a ...

  8. Coupling hydrological and impact assessment models to explore nutrient cycling in freshwater systems

    Science.gov (United States)

    Bouwman, Lex; van Beek, Rens; Beusen, Arthur; Mogollón, José; Middelburg, Jack

    2016-04-01

    The IMAGE-Global Nutrient Model (GNM) is a new globally distributed, spatially explicit model in which the hydrology model PCR-GLOBWB is coupled to the integrated assessment model IMAGE to simulate nitrogen (N) and phosphorus (P) delivery, and then with a spiraling ecological approach to simulating instream biogeochemistry. Routing the water with dissolved and suspended N and P from upstream grid cells occurs simultaneous with N and P delivery to water bodies within grid cells from diffuse and point sources (wastewater). IMAGE-GNM describes the following diffuse sources associated with the water flow: surface runoff, shallow and deep groundwater, riparian zones. Depending on the landscape features, all these flows may be present within one grid cell. Furthermore, diffuse N and P inputs occur through allochtonous organic matter inputs via litterfall in (temporarily) inundated river floodplains, and atmospheric deposition. In the spiraling concept, the residence time of the water and nutrient uptake velocity determine N and P retention in water bodies. Validation of model results with observations yields acceptable agreement given the global scale of the uncalibrated model. Sensitivity analysis shows shifts in the importance of the different sources, with decreasing importance of natural sources and increasing influence of wastewater and agriculture. IMAGE-GNM can be employed to study the interaction between society and the environment over prolonged time periods. Here we show results for the full 20th century.

  9. Application of base-level cycles to sandstone-type uranium deposit: taking Dongsheng uranium deposits as an example

    International Nuclear Information System (INIS)

    Yang Renchao; Han Zuozhen; Fan Aiping; Chang Xiangchun

    2006-01-01

    High-resolution sequence stratigraphy taking base-level cycles as interface of reference was developed rapidly in recent years. Its greatest predominance lies in that it can be applied to multi-controled continental sedimentary basins and can effectively improve accuracy and distinguishability of sequence stratigraphy analysis. Principles of base-level cycles can also be applied to the research and practice of the exploration and exploitation of sandstone-type uranium deposits as they control the spatial distribution, porosity, the permeability and the sealing ability of sandstone and mudstone, and stacking patterns of strata configuration. Taking Dongsheng uranium deposits as an example, the application of base-level cycles to exploration and exploitation of sandstone uranium deposits was analyzed. It is suggested that favorable strata framework of sandstone and mudstone was developed very well in the fluctuation of base-level cycles. Sand bodies were provided with good connectedness, coarse granularity, high debris content, low matrix content and good porosity-permeability becoming the most important uranium hosted strata. (authors)

  10. Nutrient stoichiometry in Sphagnum along a nitrogen deposition gradient in highly polluted region of Central-East Europe

    Energy Technology Data Exchange (ETDEWEB)

    Jirousek, Martin, E-mail: machozrut@mail.muni.c [Department of Botany and Zoology, Faculty of Science, Masaryk University, Kotlarska 2, 61137 Brno (Czech Republic); Hajek, Michal [Department of Botany and Zoology, Faculty of Science, Masaryk University, Kotlarska 2, 61137 Brno (Czech Republic); Bragazza, Luca [WSL Swiss Federal Institute for Forest, Snow and Landscape Research, Site Lausanne, Station 2, Case Postale 96, CH-1015 Lausanne (Switzerland); Ecole Polytechnique Federale de Lausanne (EPFL), Laboratory of Ecological Systems - ECOS, Batiment GR, Station 2, CH-1015 Lausanne (Switzerland); Department of Biology and Evolution, University of Ferrara, Corso Ercole I d' Este 32, I-44100 Ferrara (Italy)

    2011-02-15

    We investigated the variation of N:P and N:K ratio in ombrotrophic Sphagnum plants along a gradient of atmospheric N deposition from 1 to 2.5 g m{sup -2} year{sup -1} in Central-East Europe. The N:P and N:K ratio in Sphagnum capitula increased significantly along the N deposition gradient. Sphagnum species from the Cuspidata section were characterised by significantly lower ratios at low N deposition. When we compared the observed N:P ratios in Sphagnum plants with the values reported in a previous European-wide study, we found a correspondence in nutrient stoichiometry only for a few bogs: higher P concentration in Sphagnum capitula caused a lower N:P ratio in most of the study bogs so that Sphagnum plants still seem N-limited despite their N saturation. Interaction between summer water table decrease and aerial liming of surrounding forests is proposed as an explanation for this discrepancy. Local forestry practice interacting with climate thus alter N:P stoichiometry of Sphagnum along the N deposition gradient. - Research highlights: Despite high atmopsheric nitrogen deposition, Sphagnum mosses still have rather low N:P ratio. Regional climate and landscape management can enhance P and K availability in bogs. Sphagnum species of the Cuspidata section were characterised by lower N:P ratio. - Regional climate and local forestry practices are expected to alter nutrient stoichiometry in Sphagnum mosses at high atmospheric N deposition in Central-East Europe.

  11. Nutrient stoichiometry in Sphagnum along a nitrogen deposition gradient in highly polluted region of Central-East Europe

    International Nuclear Information System (INIS)

    Jirousek, Martin; Hajek, Michal; Bragazza, Luca

    2011-01-01

    We investigated the variation of N:P and N:K ratio in ombrotrophic Sphagnum plants along a gradient of atmospheric N deposition from 1 to 2.5 g m -2 year -1 in Central-East Europe. The N:P and N:K ratio in Sphagnum capitula increased significantly along the N deposition gradient. Sphagnum species from the Cuspidata section were characterised by significantly lower ratios at low N deposition. When we compared the observed N:P ratios in Sphagnum plants with the values reported in a previous European-wide study, we found a correspondence in nutrient stoichiometry only for a few bogs: higher P concentration in Sphagnum capitula caused a lower N:P ratio in most of the study bogs so that Sphagnum plants still seem N-limited despite their N saturation. Interaction between summer water table decrease and aerial liming of surrounding forests is proposed as an explanation for this discrepancy. Local forestry practice interacting with climate thus alter N:P stoichiometry of Sphagnum along the N deposition gradient. - Research highlights: → Despite high atmopsheric nitrogen deposition, Sphagnum mosses still have rather low N:P ratio.→ Regional climate and landscape management can enhance P and K availability in bogs. → Sphagnum species of the Cuspidata section were characterised by lower N:P ratio. - Regional climate and local forestry practices are expected to alter nutrient stoichiometry in Sphagnum mosses at high atmospheric N deposition in Central-East Europe.

  12. Context-dependent consequences of Marenzelleria spp. (Spionidae: Polychaeta invasion for nutrient cycling in the Northern Baltic Sea

    Directory of Open Access Journals (Sweden)

    Alexey Maximov

    2015-10-01

    Full Text Available Marenzelleria spp. are among the most successful non-native benthic species in the Baltic Sea. These burrowing polychaetes dig deeper than most native Baltic species, performing previously lacking ecosystem functions. We examine evidence from experiments, field sampling and modelling that the introduction of Marenzelleria spp. affects nutrient cycling and biogeochemical processes at the sediment–water interface. Over longer time scales, bioirrigation by Marenzelleria spp. has the potential to increase phosphorus retention in bottom deposits because of deeper oxygen penetration into sediments and formation of a deeper oxidized layer. In contrast, nitrogen fluxes from the sediment increase. As a consequence of a decline of the phosphate concentration and/or rising nitrogen/phosphorus ratio, some Northern Baltic ecosystems may experience improvement of the environment because of mitigation of eutrophication and harmful cyanobacteria blooms. Although it is difficult to unambiguously estimate the ecosystem-level consequences of invasion, in many cases it could be considered as positive due to increased structural and functional diversity. The long-term interactions with the native fauna still remain unknown, however, and in this paper we highlight the major knowledge gaps.

  13. Modelling and mapping of spatial differentiated impacts of nitrogen input to ecosystems within the framework of the UNECE-Convention of Air Pollution Prevention. Part I. Simulations of nutrient cycle and leaching form German forest ecosystems considering changes in deposition and climate; Modellierung und Kartierung raeumlich differenzierter Wirkungen von Stickstoffeintraegen in Oekosysteme im Rahmen der UNECE-Luftreinhaltekonvention. Teilbericht I. Simulationen oekosystemarer Stoffumsetzungen und Stoffaustraege aus Waldoekosystemen in Duetschland unter Beruecksichtigung geaenderter Stoffeintraege und Klimabedingungen

    Energy Technology Data Exchange (ETDEWEB)

    Wochele, Sandra; Kiese, Ralf; Butterbach-Bahl, Klaus; Grote, R. [Karlsruhe Institute of Technology (KIT), Garmisch-Partenkirchen (DE). Inst. for Meteorology and Climate Research Atmospheric Environmental Research (IMK-IFU)

    2010-03-15

    Semi-natural ecosystems are exposed to high atmospheric deposition for decades. In contrary to sulphur deposition which could be significantly reduced due to international conventions on air pollution prevention during the last decades, deposition of both, reduced and oxidized nitrogen is still on a very high level in average 40 kg N ha{sup -1} yr{sup -1} in forest ecosystems in Germany. The FuE-Project ''Modelling and mapping of spatial differentiated impacts of nitrogen input to ecosystems within the framework of the UNECE - Convention of Air Pollution Prevention'' was jointly conducted by 4 partner institutions and studied impacts of atmospheric nitrogen deposition and climate change on physico-chemical properties of forest soils, nutrient storage and nutrient export (Karlsruhe Institute of Technology, IMK-IFU) as well as biodiversity of vegetation (OeKO-DATA and Waldkunde Institute Eberswalde) and soil organisms (Giessen University). Work carried out at IMK-IFU initially concentrated on the implementation of the soil acidification model SAFE into the biogeochemical model framework MoBiLE already developed at IMK-IFU. Based on different deposition and climate scenarios prediction of the soil C/N ratio, nitrogen losses (N{sub 2}O emissions) into the atmosphere and via nitrate leaching into the hydrosphere were made using the biogeochemical Forest-DNDC-SAFE model (realized from the MoBiLE framework). Additionally changes in base saturation and pH values were simulated for the period 1920-2060. Simulation results for 62 Level II sites in Germany show, that with the decline of the SO{sub 4}{sup -} deposition soil acidification could be mitigated, although sites with high nitrogen deposition (> 40 kg N ha{sup -1} yr{sup -1}) do recover slower than others with lower nitrogen deposition. At most sites the decline in nitrogen deposition did not yet lead to a regeneration concerning nutrient status (significant re-widening of the C/N ratio) and

  14. A Metagenomic Perspective on Changes to Nutrient-cycling Genes Following Forest-to-agriculture Conversion in the Amazon Basin

    Science.gov (United States)

    Meyer, K. M.; Womack, A. M.; Rodrigues, J.; Nüsslein, K.; Bohannan, B. J. M.

    2014-12-01

    Forest-to-agriculture conversion has been shown to alter nutrient cycling and the community composition of soil microorganisms. However, few studies have looked simultaneously at how the abundance, composition, and diversity of microbial genes involved in nutrient cycling change with conversion. We used shotgun metagenomic sequencing to analyze soil from primary rainforest and converted cattle pasture sampled at the Fazenda Nova Vida in Rondônia, Brazil. The diversity, richness, and evenness of nutrient cycling genes were significantly higher in the pasture, and the composition of nutrient cycling communities differed significantly between land use types. These results largely mirror taxonomic shifts following Amazon rainforest conversion, which tends to increase diversity, richness, and evenness of soil microbial communities. The abundance of genes related to N cycling and methane flux differed between land use types. Methanotrophy genes decreased in abundance in the pasture, whereas methanogenesis genes were not significantly different between land use types. These changes could underlie the commonly observed shift from methane sink to source following forest-to-agriculture conversion. Multiple genes in the nitrogen cycle also differed with land use, including genes related to N-fixation and ammonification. Metagenomics provides a unique perspective on the consequences of land use change on microbial community structure and function.

  15. Depositional Cycles of Muara Wahau Coals, Kutai Basin, East Kalimantan

    Directory of Open Access Journals (Sweden)

    Komang Anggayana

    2014-09-01

    Full Text Available http://dx.doi.org/10.17014/ijog.v1i2.183Fifteen samples were taken ply by ply from a 33 m thick drill core of Muara Wahau coal seams for interpretation of depositional environments. Generally, lithotype variation in the bottom part of the coal seams has a lower frequency than in the upper part. Petrographical analysis was performed to determine the maceral composition, groundwater index (GWI, and gelification index (GI. The samples from lower sections show much higher GWI-GI values and lower variation frequency than from the upper section. This characteristic is interpreted as the result of development of mesotrophic to ombrotrophic peats during the deposition of lower to upper parts of the section, respectively. During the development of the mesotrophic peat, water was more abundant and relatively stable in budget. However, during the development of ombrotrophic peat, water was less abundant and relatively not stable in budget. The latter is related to the water supply depending only on rain, resulted in the more sensitive water table in the om- brotrophic peat. The unstable water table is thought as the reason of higher variation frequency of lithotype, GWI, GI, as well as maceral composition in the upper part of the core. Unstable water table would lead to moist condition in the uppermost layer of the ombrotrophic peat, favoring fungi to grow. This is confirmed by the higher abundance of sclerotinite maceral in samples from the upper part of the coal core.

  16. Including Life Cycle Assessment for decision-making in controlling wastewater nutrient removal systems

    DEFF Research Database (Denmark)

    Corominas, Lluís; Larsen, Henrik Fred; Flores-Alsina, Xavier

    2013-01-01

    of the impact categories is conducted to assess how value choices (policy decisions) may affect the management of WWTPs. For the scenarios with only N-limitation, the LCA-based ranking of the control strategies is sensitive to the choice of weighting factors, whereas this is not the case for N&P or P......This paper focuses on the use of Life Cycle Assessment (LCA) to evaluate the performance of seventeen control strategies in wastewater treatment plants (WWTPs). It tackles the importance of using site-specific factors for nutrient enrichment when decision-makers have to select best operating....../or energy savings present an environmental benefit for N&P and P-deficient systems. This is not the case when addressing N-deficient systems for which the use of chemicals (even for improving N removal efficiencies) is not always beneficial for the environment. A sensitivity analysis on using weighting...

  17. Pharmaceutical consumption and residuals potentially relevant to nutrient cycling in Greater Accra, Ghana

    Directory of Open Access Journals (Sweden)

    Evren Sinar

    2010-04-01

    Full Text Available Recycling nutrients form sanitary wastes back into agricultural ecosystems offers an option to alleviate soil depletion in regions where the use of mineral fertiliser is limited. Exemplary nutrient and water cycling approaches, including collection, treatment and use of human urine, are established at Valley View University (VVU in Greater Accra, Ghana.Concerns have been recently raised in regard to fate and impact of pharmaceutical residues in soils and interlinked environment. To evaluate in how far emerging knowledge can be transposed onto VVU, urban and rural environments in Greater Accra, spatial disease occurrence and drug consumption patterns were studied. Malaria has been found to represent the most severe health burden in Ghana, but there is also a high prevalence of infectious diseases. Drugs consumed in great quantities and in respect to their residual loads potentially problematic in the environment belong to therapeutic groups of: antibiotics, analgesics, drugs for diabetes, antimalarials, cardiovascular drugs and anthelmintics. Drug consumption revealed to be highest in urban and lowest in rural areas. At VVU the range of consumed drugs is comparable to urban areas except for the negligible use of diabetes and cardiovascular medication as well as contraceptives.

  18. Nutrient cycling, connectivity, and free-floating plant abundance in backwater lakes of the Upper Mississippi River

    Science.gov (United States)

    Houser, Jeff N.; Giblin, Shawn M.; James, William F.; Langrehr, H.A.; Rogala, James T.; Sullivan, John F.; Gray, Brian R.

    2013-01-01

    River eutrophication may cause the formation of dense surface mats of free floating plants (FFP; e.g., duckweeds and filamentous algae) which may adversely affect the ecosystem. We investigated associations among hydraulic connectivity to the channel, nutrient cycling, FFP, submersed aquatic vegetation (SAV), and dissolved oxygen concentration (DO) in ten backwater lakes of the Upper Mississippi River (UMR) that varied in connectivity to the channel. Greater connectivity was associated with higher water column nitrate (NO3-N) concentration, higher rates of sediment phosphorus (P) release, and higher rates of NO3-N flux to the sediments. Rates of sediment P and N (as NH4-N) release were similar to those of eutrophic lakes. Water column nutrient concentrations were high, and FFP tissue was nutrient rich suggesting that the eutrophic condition of the UMR often facilitated abundant FFP. However, tissue nutrient concentrations, and the associations between FFP biomass and water column nutrient concentrations, suggested that nutrients constrained FFP abundance at some sites. FFP abundance was positively associated with SAV abundance and negatively associated with dissolved oxygen concentration. These results illustrate important connections among hydraulic connectivity, nutrient cycling, FFP, SAV, and DO in the backwaters of a large, floodplain river.

  19. Atmospheric deposition as a source of carbon and nutrients to an alpine catchment of the Colorado Rocky Mountains

    Science.gov (United States)

    Mladenov, N.; Williams, M. W.; Schmidt, S. K.; Cawley, K.

    2012-08-01

    Many alpine areas are experiencing deglaciation, biogeochemical changes driven by temperature rise, and changes in atmospheric deposition. There is mounting evidence that the water quality of alpine streams may be related to these changes, including rising atmospheric deposition of carbon (C) and nutrients. Given that barren alpine soils can be severely C limited, atmospheric deposition sources may be an important source of C and nutrients for these environments. We evaluated the magnitude of atmospheric deposition of C and nutrients to an alpine site, the Green Lake 4 catchment in the Colorado Rocky Mountains. Using a long-term dataset (2002-2010) of weekly atmospheric wet deposition and snowpack chemistry, we found that volume weighted mean dissolved organic carbon (DOC) concentrations were 1.12 ± 0.19 mg l-1, and weekly concentrations reached peaks as high at 6-10 mg l-1 every summer. Total dissolved nitrogen concentration also peaked in the summer, whereas total dissolved phosphorus and calcium concentrations were highest in the spring. To investigate potential sources of C in atmospheric deposition, we evaluated the chemical quality of dissolved organic matter (DOM) and relationships between DOM and other solutes in wet deposition. Relationships between DOC concentration, fluorescence, and nitrate and sulfate concentrations suggest that pollutants from nearby urban and agricultural sources and organic aerosols derived from sub-alpine vegetation may influence high summer DOC wet deposition concentrations. Interestingly, high DOC concentrations were also recorded during "dust-in-snow" events in the spring, which may reflect an association of DOM with dust. Detailed chemical and spectroscopic analyses conducted for samples collected in 2010 revealed that the DOM in many late spring and summer samples was less aromatic and polydisperse and of lower molecular weight than that of winter and fall samples. Our C budget estimates for the Green Lake 4 catchment

  20. Paleoproductivity and Nutrient Cycling on the Sumatra Margin during the Past Half Million Years

    Science.gov (United States)

    Gibson, K.; Mitt Schwamborn, T.; Thunell, R.; Tuten, E. C.; Swink, C.; Tappa, E.

    2017-12-01

    In the IndoPacific, changes in paleoproductivity on orbital timescales are often linked to changes in precession, particularly in areas of coastal upwelling. These changes are in turn related to variations in zonal wind patterns and thermocline tilt associated with the El Niño Southern Oscillation (ENSO) and the Indian Ocean Dipole (IOD), and commensurate changes in Asian, Indian, and Australian monsoon precipitation and wind-driven upwelling. Previous studies have revealed varying phase relationships amongst monsoon precipitation, upwelling variability and precession minima in the Indo-Pacific region. Regional records have additionally displayed power in the 41-kyr band, attributed to changes in deepwater ventilation and preservation, and the 100-kyr band, related to the influence of sea level on the Indonesian Throughflow (ITF). To provide further insight into the regional and distal forcing on paleoproductivity and nutrient cycling in this clearly complex region, we present %TOC, %CaCO3, and sedimentary δ15N data from core MD98-2152, off the Sumatra margin in a region influenced by both ITF variability and wind-driven upwelling. By comparing our paleoproductivity and paleonutrient data with planktonic δ18O (tuned to composite Chinese cave speleothem records) and benthic δ18O (tuned to the Lisiecki-Raymo Stack), we compare timing of local productivity changes to high latitude ice-volume changes and local hydrographic changes. A strong 23-kyr signal in the %TOC record supports the strong influence of precession on paleoproductivity in this region. In contrast, strong power in the 100 and 41-kyr bands is observed in %CaCO3 and δ15N with a relatively minor contribution from precession, indicating a complex relationship between nutrient cycling, upwelling, production, and preservation on the Sumatra coast.

  1. Effects of repetitive droughts on carbon, nutrient and water cycles of heathland ecosystem

    Science.gov (United States)

    Rineau, Francois; Beenaerts, Natalie; Nijs, Ivan; De Boeck, Hans; Vangronsveld, Jaco

    2017-04-01

    A large body of research is now focusing on the understanding of mechanisms regulating ecosystem functioning, predictions on their activity in the long-term, and the management practices to keep them running. For this purpose, Hasselt University decided to invest in the construction of a high technological research infrastructure: the "Ecotron Hasselt University", where twelve large ecosystem replicates can be continuously monitored and controlled. The ecotrons will be fed with real-time climatic data from a nearby ICOS tower located on top of a heathland landscape. The research performed there will focus on understanding the response of heathland ecosystem services (ES) to yearly repeated droughts of different intensities. We aim to perform as well an economical valuation of these ES. From a biological point of view, we will measure soil processes that drive the three most valuable ES: water, C and nutrient cycles, and especially how soil organisms affect them, through which mechanisms and at different drought intensities. Species interactions and their influence on C sequestration and organic matter degradation will be also incorporated into a state-of-the art soil C cycling model.

  2. Biomass production and nutrient cycling in Eucalyptus short rotation energy forests in New Zealand. 1: biomass and nutrient accumulation

    Energy Technology Data Exchange (ETDEWEB)

    Guo, L.B.; Sims, R.E.H. [Massey University, Palmerston North (New Zealand). Institute of Technology and Engineering; Horne, D.J. [Massey University, Palmerston North (New Zealand). Institute of Natural Resources

    2002-12-01

    Accumulation of biomass and nutrients (N, P, K, Ca, Mg and Mn) was measured during the first 3- year rotation of three Eucalyptus short rotation forest species (E. botryoides, E. globulus and E. ovata) irrigated with meatworks effluent compared with no irrigation. E. globulus had the highest biomass and nutrient accumulation either irrigated with effluent or without irrigation. After 3-year growth, E. globulus stands irrigated with effluent accumulated 72 oven dry t/ha of above-ground total biomass with a total of 651 kg N, 55 kg P, 393 kg K, 251 kg Ca, 35 kg Mg and 67 kg Mn. Effluent irrigation increased the accumulation of biomass, N, P, K and Mn, but tended to reduce the leaf area index and leaf biomass, and decreased the accumulation of Ca and Mg. (author)

  3. Amazonian biomass burning-derived acid and nutrient deposition in the north Andean montane forest of Ecuador

    Science.gov (United States)

    Boy, Jens; Rollenbeck, Rütger; Valarezo, Carlos; Wilcke, Wolfgang

    2008-12-01

    We explored the influence of biomass burning in Amazonia and northeastern Latin America on N, C, P, S, K, Ca, Mg, Al, Mn, and Zn cycles of an Andean montane forest in south Ecuador exposed to the Amazon basin between May 1998 and April 2003. We assessed the response of the element budget of three microcatchments (8-13 ha) to the variations in atmospheric deposition between the intensive burning season and outside the burning season in Amazonia. There were significantly elevated H, N, and Mn depositions during biomass burning. Elevated H deposition during biomass burning caused elevated base metal loss from the canopy and the organic horizon and deteriorated already low base metal supply of the vegetation. N was only retained during biomass burning but not during nonfire conditions when deposition was much smaller. We conclude that biomass burning-related aerosol emissions in Amazonia are large enough to substantially increase element deposition at the western rim of Amazonia. Particularly the related increase of acid deposition impoverishes already base metal scarce ecosystems. As biomass burning is most intense during El Niño situations, a shortened El Niño-Southern Oscillation cycle because of global warming likely enhances the acid deposition at our study forest.

  4. The effects of climate change on the nitrogen cycle and acid deposition

    Energy Technology Data Exchange (ETDEWEB)

    Penner, J.E.; Walton, J.J. (Lawrence Livermore National Lab., CA (USA)); Graboske, B.C. (California Univ., Berkeley, CA (USA))

    1990-09-01

    Increases in greenhouse gases are expected to lead to a number of changes to the atmosphere which may impact regional and global chemical cycles. With the increasing awareness of climate change and the possibility of global chemical changes to the atmosphere, it becomes important to ask whether these changes to global climate and chemical cycles might benefit or hinder control programs aimed at reducing acid deposition. In the following, we review several possible changes to climate that may be expected to impact the global cycle of reactive nitrogen. We then use our global model of the reactive nitrogen cycle to estimate the effects of several of the more important changes on the continental-scale deposition of nitric acid. 7 refs., 1 tab.

  5. Environmental impacts of innovative dairy farming systems aiming at improved internal nutrient cycling: a multi-scale assessment

    NARCIS (Netherlands)

    Vries, de W.; Kros, J.; Dolman, M.A.; Vellinga, Th.V.; Boer, de H.C.; Sonneveld, M.P.W.; Bouma, J.

    2015-01-01

    Several dairy farms in the Netherlands aim at reducing environmental impacts by improving the internal nutrient cycle (INC) on their farm by optimizing the use of available on-farm resources. This study evaluates the environmental performance of selected INC farms in the Northern Friesian Woodlands

  6. A method for the division of the conglomerate depositional cycle under Milankovitch cycles

    Science.gov (United States)

    Chen, Panpan; Fang, Nianqiao; Li, Cunlei; Liu, Jianmei

    2017-06-01

    The conglomerate layer at the upper section of the 4th member of the Shahejie formation ({{{{S}}}4}{{u}}) of the Yongan district at the Donying depression is a well-developed sedimentation of several periods. It lacks stable muddy layers and sophisticated classification of the sedimentation periods and the proportion of sedimentary layering in each period has long been a difficult task for geologists. In addressing this problem, this paper attempts to introduce the theory of climatic cycles driven by astronomical periods from astronomical stratigraphy on the basis of the characteristics of the sedimentation under the turbidity current in the region of study. Through studying the conditions for the formation of the conglomerate layer and the factors of control, we pinpoint the formation of the layer in chronology and differentiate the cycle interface and correlation in the same formation period. Milankovitch analysis is conducted on the sedimentation of the conglomerate layer in the region of study to determine if the stratigraphy cycle of the region is primarily controlled by the eccentricity cycle and calculate MSC1 and MSC2 thicknesses of 189.3 m and 78.05 m, respectively. Milankovitch theory is the primary tool used in the analysis, in conjunction with petrographic analysis. The stratum at the {{{{S}}}4}{{u}} is classified into four IV-grade sequences and 11 V-grade sequences. The information on the dominant cycle frequency is used for wave filtering of the well logs and to determine the significant Milankovitch wave log. With the data from this curve, we may compare the stratigraphy cycle with the characteristics of the standard cycle and classify and compare the sedimentation periods of the conglomerate layers in further detail.

  7. Nutrient limitation reduces land carbon uptake in simulations with a model of combined carbon, nitrogen and phosphorus cycling

    Directory of Open Access Journals (Sweden)

    D. S. Goll

    2012-09-01

    Full Text Available Terrestrial carbon (C cycle models applied for climate projections simulate a strong increase in net primary productivity (NPP due to elevated atmospheric CO2 concentration during the 21st century. These models usually neglect the limited availability of nitrogen (N and phosphorus (P, nutrients that commonly limit plant growth and soil carbon turnover. To investigate how the projected C sequestration is altered when stoichiometric constraints on C cycling are considered, we incorporated a P cycle into the land surface model JSBACH (Jena Scheme for Biosphere–Atmosphere Coupling in Hamburg, which already includes representations of coupled C and N cycles.

    The model reveals a distinct geographic pattern of P and N limitation. Under the SRES (Special Report on Emissions Scenarios A1B scenario, the accumulated land C uptake between 1860 and 2100 is 13% (particularly at high latitudes and 16% (particularly at low latitudes lower in simulations with N and P cycling, respectively, than in simulations without nutrient cycles. The combined effect of both nutrients reduces land C uptake by 25% compared to simulations without N or P cycling. Nutrient limitation in general may be biased by the model simplicity, but the ranking of limitations is robust against the parameterization and the inflexibility of stoichiometry. After 2100, increased temperature and high CO2 concentration cause a shift from N to P limitation at high latitudes, while nutrient limitation in the tropics declines. The increase in P limitation at high-latitudes is induced by a strong increase in NPP and the low P sorption capacity of soils, while a decline in tropical NPP due to high autotrophic respiration rates alleviates N and P limitations. The quantification of P limitation remains challenging. The poorly constrained processes of soil P sorption and biochemical mineralization are identified as the main uncertainties in the strength of P limitation

  8. Evaluating the effect of nutrient redistribution by animals on the phosphorus cycle of lowland Amazonia

    Directory of Open Access Journals (Sweden)

    C. Buendía

    2018-01-01

    Full Text Available Phosphorus (P availability decreases with soil age and potentially limits the productivity of ecosystems growing on old and weathered soils. Despite growing on ancient soils, ecosystems of lowland Amazonia are highly productive and are among the most biodiverse on Earth. P eroded and weathered in the Andes is transported by the rivers and deposited in floodplains of the lowland Amazon basin creating hotspots of P fertility. We hypothesize that animals feeding on vegetation and detritus in these hotspots may redistribute P to P-depleted areas, thus contributing to dissipate the P gradient across the landscape. Using a mathematical model, we show that animal-driven spatial redistribution of P from rivers to land and from seasonally flooded to terra firme (upland ecosystems may sustain the P cycle of Amazonian lowlands. Our results show how P imported to land by terrestrial piscivores in combination with spatial redistribution of herbivores and detritivores can significantly enhance the P content in terra firme ecosystems, thereby highlighting the importance of food webs for the biogeochemical cycling of Amazonia.

  9. Evaluating the effect of nutrient redistribution by animals on the phosphorus cycle of lowland Amazonia

    Science.gov (United States)

    Buendía, Corina; Kleidon, Axel; Manzoni, Stefano; Reu, Björn; Porporato, Amilcare

    2018-01-01

    Phosphorus (P) availability decreases with soil age and potentially limits the productivity of ecosystems growing on old and weathered soils. Despite growing on ancient soils, ecosystems of lowland Amazonia are highly productive and are among the most biodiverse on Earth. P eroded and weathered in the Andes is transported by the rivers and deposited in floodplains of the lowland Amazon basin creating hotspots of P fertility. We hypothesize that animals feeding on vegetation and detritus in these hotspots may redistribute P to P-depleted areas, thus contributing to dissipate the P gradient across the landscape. Using a mathematical model, we show that animal-driven spatial redistribution of P from rivers to land and from seasonally flooded to terra firme (upland) ecosystems may sustain the P cycle of Amazonian lowlands. Our results show how P imported to land by terrestrial piscivores in combination with spatial redistribution of herbivores and detritivores can significantly enhance the P content in terra firme ecosystems, thereby highlighting the importance of food webs for the biogeochemical cycling of Amazonia.

  10. Wetland development, permafrost history and nutrient cycling inferred from late Holocene peat and lake sediment records in subarctic Sweden

    DEFF Research Database (Denmark)

    Kokfelt, U.; Reuss, N.; Struyf, E.

    2010-01-01

    Sweden to address the late Holocene (5,000 cal BP-present) development of the mire as well as related changes in carbon and nutrient cycling. Formation, sediment accumulation and biogeochemistry of two studied lakes are suggested to be largely controlled by the development of the mire and its permafrost......-induced changes in hydrology may further have affected the inflow of alkaline water from the catchment. Elevated contents of biogenic silica and diatom pigments in lake sediments during periods of poor fen and bog expansion further indicate that terrestrial vegetation influenced the amount of nutrients entering...

  11. Nutrient solution aeration and growing cycles affect quality and yield of fresh-cut baby leaf red lettuce

    Directory of Open Access Journals (Sweden)

    Encarnación Conesa

    2015-12-01

    Full Text Available The objective of this research was to study the effects of nutrient solution aeration [no aeration (NA, low aeration (LA or high aeration (HA] and growing cycle (autumn, winter and summer on the yield, quality, and shelf life of red lettuce as a fresh-cut product grown in a floating system. The specific leaf area, yield and root diameter were affected by the growing cycle. The percentage of dry matter and the nitrate content were affected by growing cycle and aeration, total phenolics and mesophilic microorganism by aeration and storage time, hue angle and chromacity by growing cycle and storage time, and antioxidant capacity, vitamin C, lightness and psychrophilic microorganisms were affected by all three factors. NA conditions increased the antioxidant capacity in summer and vitamin C content in winter. The lowest mesophilic and psychrophilic count was observed in autumn. The effect of aeration on most of the quality parameters measured was influenced by the growing cycle.

  12. Sampling strategies for tropical forest nutrient cycling studies: a case study in São Paulo, Brazil

    Directory of Open Access Journals (Sweden)

    G. Sparovek

    1997-12-01

    Full Text Available The precise sampling of soil, biological or micro climatic attributes in tropical forests, which are characterized by a high diversity of species and complex spatial variability, is a difficult task. We found few basic studies to guide sampling procedures. The objective of this study was to define a sampling strategy and data analysis for some parameters frequently used in nutrient cycling studies, i. e., litter amount, total nutrient amounts in litter and its composition (Ca, Mg, Κ, Ν and P, and soil attributes at three depths (organic matter, Ρ content, cation exchange capacity and base saturation. A natural remnant forest in the West of São Paulo State (Brazil was selected as study area and samples were collected in July, 1989. The total amount of litter and its total nutrient amounts had a high spatial independent variance. Conversely, the variance of litter composition was lower and the spatial dependency was peculiar to each nutrient. The sampling strategy for the estimation of litter amounts and the amount of nutrient in litter should be different than the sampling strategy for nutrient composition. For the estimation of litter amounts and the amount of nutrients in litter (related to quantity a large number of randomly distributed determinations are needed. Otherwise, for the estimation of litter nutrient composition (related to quality a smaller amount of spatially located samples should be analyzed. The determination of sampling for soil attributes differed according to the depth. Overall, surface samples (0-5 cm showed high short distance spatial dependent variance, whereas, subsurface samples exhibited spatial dependency in longer distances. Short transects with sampling interval of 5-10 m are recommended for surface sampling. Subsurface samples must also be spatially located, but with transects or grids with longer distances between sampling points over the entire area. Composite soil samples would not provide a complete

  13. Aboveground persistence of vascular plants in relationship to the levels of airborne nutrient deposition

    NARCIS (Netherlands)

    Hendriks, R.J.J.; Ozinga, W.A.; Berg, van den L.J.L.; Noordwijk, E.; Schaminee, J.H.J.; Groenendael, van J.M.

    2014-01-01

    This paper examines whether high atmospheric nitrogen deposition affects aboveground persistence of vascular plants. We combined information on local aboveground persistence of vascular plants in 245 permanent plots in the Netherlands with estimated level of nitrogen deposition at the time of

  14. Effects of nitrogen deposition on carbon cycle in terrestrial ecosystems of China: A meta-analysis

    International Nuclear Information System (INIS)

    Chen, Hao; Li, Dejun; Gurmesa, Geshere A.; Yu, Guirui; Li, Linghao; Zhang, Wei; Fang, Huajun; Mo, Jiangming

    2015-01-01

    Nitrogen (N) deposition in China has increased greatly, but the general impact of elevated N deposition on carbon (C) dynamics in Chinese terrestrial ecosystems is not well documented. In this study we used a meta-analysis method to compile 88 studies on the effects of N deposition C cycling on Chinese terrestrial ecosystems. Our results showed that N addition did not change soil C pools but increased above-ground plant C pool. A large decrease in below-ground plant C pool was observed. Our result also showed that the impacts of N addition on ecosystem C dynamics depend on ecosystem type and rate of N addition. Overall, our findings suggest that 1) decreased below-ground plant C pool may limit long-term soil C sequestration; and 2) it is better to treat N-rich and N-limited ecosystems differently in modeling effects of N deposition on ecosystem C cycle. - Highlights: • Meta-analysis was used to address the effects of N addition on C cycle. • N addition caused an large decease in belowground plant C pool. • N-rich and N-limited ecosystems had different responses to N addition. - N addition caused a large decrease in below-ground plant C pool.

  15. Energy and nutrient deposition and excretion in the reproducing sow: model development and evaluation

    DEFF Research Database (Denmark)

    Hansen, A V; Strathe, A B; Theil, Peter Kappel

    2014-01-01

    was related to predictions of body fat and protein loss from the lactation model. Nitrogen intake, urine N, fecal N, and milk N were predicted with RMSPE as percentage of observed mean of 9.7, 17.9, 10.0, and 7.7%, respectively. The model provided a framework, but more refinements and improvements in accuracy......Air and nutrient emissions from swine operations raise environmental concerns. During the reproduction phase, sows consume and excrete large quantities of nutrients. The objective of this study was to develop a mathematical model to describe energy and nutrient partitioning and predict manure...... excretion and composition and methane emissions on a daily basis. The model was structured to contain gestation and lactation modules, which can be run separately or sequentially, with outputs from the gestation module used as inputs to the lactation module. In the gestating module, energy and protein...

  16. Metagenomic Insights Into the Microbial Community and Nutrient Cycling in the Western Subarctic Pacific Ocean

    Directory of Open Access Journals (Sweden)

    Yingdong Li

    2018-04-01

    Full Text Available The composition and metabolic functions of prokaryotic communities in the western subarctic Pacific (WSP, where strong mixing of waters from the Sea of Okhotsk and the East Kamchatka Current result in transfer to the Oyashio Current, were investigated using a shotgun metagenome sequencing approach. Functional metabolic genes related to nutrient cycling of nitrogen, sulfur, carbohydrates, iron and amino acids were differently distributed between the surface and deep waters of the WSP. Genes related to nitrogen metabolism were mainly found in deep waters, where Thaumarchaeaota, Sphingomonadales, and Pseudomonadales were closely associated and performing important roles in ammonia oxidation, assimilatory nitrate reduction, and dissimilatory nitrate reduction processes, respectively. In addition, orders affiliated to Spingobacteria and Alphaproteobacteria were crucial for sulfate reduction and abundant at 3000 m, whereas orders affiliated to Gammaproteobacteria, which harbored the most sulfate reduction genes, were abundant at 1000 m. Additionally, when compared with the East Kamchatka Current, the prokaryotes in the Oyashio Current were likely to consume more energy for synthesizing cellular components. Also, genes encoding iron transport and siderophore biosynthesis proteins were in low abundance, indicating that the iron was not a limiting factor in the Oyashio current. In contrast, in the East Kamchatka Current, prokaryotes were more likely to directly utilize the amino acids and absorb iron from the environment. Overall, our data indicated that the transformation from the East Kamchatka Current to the Oyashio Current reshapes not only the composition of microbial community, but also the function of the metabolic processes. These results extended our knowledge of the microbial composition and potential metabolism in the WSP.

  17. Metagenomic Insights Into the Microbial Community and Nutrient Cycling in the Western Subarctic Pacific Ocean.

    Science.gov (United States)

    Li, Yingdong; Jing, Hongmei; Xia, Xiaomin; Cheung, Shunyan; Suzuki, Koji; Liu, Hongbin

    2018-01-01

    The composition and metabolic functions of prokaryotic communities in the western subarctic Pacific (WSP), where strong mixing of waters from the Sea of Okhotsk and the East Kamchatka Current result in transfer to the Oyashio Current, were investigated using a shotgun metagenome sequencing approach. Functional metabolic genes related to nutrient cycling of nitrogen, sulfur, carbohydrates, iron and amino acids were differently distributed between the surface and deep waters of the WSP. Genes related to nitrogen metabolism were mainly found in deep waters, where Thaumarchaeaota, Sphingomonadales , and Pseudomonadales were closely associated and performing important roles in ammonia oxidation, assimilatory nitrate reduction, and dissimilatory nitrate reduction processes, respectively. In addition, orders affiliated to Spingobacteria and Alphaproteobacteria were crucial for sulfate reduction and abundant at 3000 m, whereas orders affiliated to Gammaproteobacteria , which harbored the most sulfate reduction genes, were abundant at 1000 m. Additionally, when compared with the East Kamchatka Current, the prokaryotes in the Oyashio Current were likely to consume more energy for synthesizing cellular components. Also, genes encoding iron transport and siderophore biosynthesis proteins were in low abundance, indicating that the iron was not a limiting factor in the Oyashio current. In contrast, in the East Kamchatka Current, prokaryotes were more likely to directly utilize the amino acids and absorb iron from the environment. Overall, our data indicated that the transformation from the East Kamchatka Current to the Oyashio Current reshapes not only the composition of microbial community, but also the function of the metabolic processes. These results extended our knowledge of the microbial composition and potential metabolism in the WSP.

  18. Multiple constraint modeling of nutrient cycling stoichiometry following forest clearing and pasture abandonment in the Eastern Amazon

    Science.gov (United States)

    Davidson, Eric; Nifong, Rachel

    2017-04-01

    While deforestation has declined since its peak, land-use change continues to modify Amazonian landscapes. The responses and feedbacks of biogeochemical cycles to these changes play an important role in determining possible future trajectories of ecosystem function and for land stewardship through effects on rates of secondary forest regrowth, soil emissions of greenhouse gases, inputs of nutrients to groundwater and streamwater, and nutrient management in agroecosystems. Here we present a new synthetic analyses of data from the NASA-supported LBA-ECO project and others datasets on nutrient cycling in cattle pastures, secondary forests, and mature forests at Paragominas, Pará, Brazil. We have developed a stoichiometric model relating C-N-P interactions during original forest clearing, extensive and intensive pasture management, and secondary forest regrowth, constrained by multiple observations of ecosystem stocks and fluxes in each land use. While P is conservatively cycled in all land uses, we demonstrate that pyrolyzation of N during pasture formation and during additional burns for pasture management depletes available-N pools, consistent with observations of lower rates of N leaching and trace gas emission and consistent with secondary forest growth responses to experimental N amendments. The soils store large stocks of N and P, and our parameterization of available forms of these nutrients for steady-state dynamics in the mature forest yield reasonable estimates of net N and P mineralization available for grasses and secondary forest species at rates consistent with observed biomass accumulation and productivity in these modified ecosystems. Because grasses and forests have much different demands for N relative to P, the land use has important biogeochemical impacts. The model demonstrates the need for periodic P inputs for sustainable pasture management and for a period of significant biological N fixation for early-to-mid-successional secondary forest

  19. CICLAJE Y PÉRDIDA DE NUTRIENTES DEL SUELO EN BOSQUES ALTOANDINOS DE ANTIOQUIA, COLOMBIA NUTRIENT CYCLING AND NUTRIENT LOSSES IN ANDEAN MONTANE FORESTS FROM ANTIOQUIA, COLOMBIA

    Directory of Open Access Journals (Sweden)

    Adriana Londoño Álvarez

    2007-06-01

    Full Text Available El agua gravitacional y su composición química fueron medidos en bosques montanos de Quercus humboldtii y reforestados (Pinus patula y Cupressus lusitanica de la región de Piedras Blancas, Antioquia (Colombia, por un período de tiempo de dos años. Se utilizaron lisímetros sin tensión con el fin de estimar el agua gravitacional y los flujos de nutrientes a diferentes profundidades en el perfil del suelo. El mayor valor anual de agua gravitacional en el nivel más profundo (50- 80 cm, fue hallado en la cobertura de ciprés ( 492,7 mm, seguido por pino pátula ( 14,2 mm y roble ( 2,0 mm. De manera similar ocurrió con la pérdida de nutrientes, mostrando el mismo patrón hallado para el agua gravitacional. Así, para roble, pátula y ciprés, en su orden, se presentaron los siguientes valores de pérdida: Ca: 0,004, 0,084 y 2,270 kg ha-1 año-1; P: 0,008, 0,052 y 1,234 kg ha-1 año-1; Mg: 0,004, 0,022 y 0,667 kg ha-1 año-1. De K se registraron 0,08 y 7,092 kg ha-1 año-1 para roble y ciprés respectivamente. Estos flujos siguieron el siguiente orden según cobertura, roble: K>P>Ca>Mg, pátula: Ca>Fe>P>Mg>Zn>Mn, y ciprés: K>Mn>Ca>P>Fe>Zn>Mg.Gravitational flow and its chemical composition were measured in montane oak forests (Quercus humboldtii, in pine (Pinus patula and cypress (Cupressus lusitanica plantations in Piedras Blancas, Antioquia ( Colombia , over two years. Zero tension lysimeters were used at different depth soil levels. The highest gravitational flow value at highest depth (50- 80 cm was obtained in cypress plot ( 492,7 mm, followed by pine ( 14,2 mm and oak forest ( 2,0 mm. A similar behavior was encountered for nutrient losses, following the same pattern as gravitational flow. Thus, for oak, pine and cypress, nutrient losses were respectively: Ca: 0,004, 0,084 and 2,270 kg ha-1 y-1; P: 0,008, 0,052 and 1,234 kg ha-1 y -1; Mg: 0,004, 0,022 and 0,667 kg ha-1 y-1. K losses were 0,08 and 7,092 kg ha-1 y-1 for oak forest and

  20. Effects of freeze-thaw cycles on microarthropods and nutrient availability in a sub-arctic soil

    DEFF Research Database (Denmark)

    Sjursen, Heidi; Michelsen, Anders; Holmstrup, Martin

    2005-01-01

    and their environment, intact plant-soil samples from the sub-Arctic were subjected to a series of such events. Springtail and mite species composition and abundance were monitored at intervals throughout the experiment. Furthermore, nutrient content and mobilisation in the soil and soil microbial biomass and nutrient......It is predicted that Arctic regions may experience an increase in mean temperature in the future. This will affect the frequency of severe climatic events such as summer droughts and freeze-thaw cycles. In order to understand the impact of recurring freezing and thawing on soil organisms...... content were examined. There was no conclusive evidence that recurring freeze-thaw events had a negative effect on the investigated soil faunal groups, and the treatment even seemed to stimulate the abundance of Acaridida. Respiration of soil subjected to 16 freeze-thaw cycles was low when kept at -2 °C...

  1. Effects of Fallow Genealogical Cycles on the Build-up of Nutrients in ...

    African Journals Online (AJOL)

    Dr Osondu

    2012-01-04

    Jan 4, 2012 ... generations. As usual, nutrients in the fallow generations were confined to the topsoil. The increase in soil nutrients was attributed to the increased in tree size, vegetation cover and ... years, is termed 1st generation fallow, one that is ...... ns: Difference between means is not significant at 5% alpha level.

  2. Nutrient stoichiometry in Sphagnum along a nitrogen deposition gradient in highly polluted region of Central-East Europe.

    Science.gov (United States)

    Jiroušek, Martin; Hájek, Michal; Bragazza, Luca

    2011-02-01

    We investigated the variation of N:P and N:K ratio in ombrotrophic Sphagnum plants along a gradient of atmospheric N deposition from 1 to 2.5 g m(-2) year(-1) in Central-East Europe. The N:P and N:K ratio in Sphagnum capitula increased significantly along the N deposition gradient. Sphagnum species from the Cuspidata section were characterised by significantly lower ratios at low N deposition. When we compared the observed N:P ratios in Sphagnum plants with the values reported in a previous European-wide study, we found a correspondence in nutrient stoichiometry only for a few bogs: higher P concentration in Sphagnum capitula caused a lower N:P ratio in most of the study bogs so that Sphagnum plants still seem N-limited despite their N saturation. Interaction between summer water table decrease and aerial liming of surrounding forests is proposed as an explanation for this discrepancy. Local forestry practice interacting with climate thus alter N:P stoichiometry of Sphagnum along the N deposition gradient. Copyright © 2010 Elsevier Ltd. All rights reserved.

  3. River Metabolism and Nutrient Cycling at the Point Scale: Insights from In Situ Sensors in Benthic Chambers

    Science.gov (United States)

    Cohen, M. J.; Reijo, C. J.; Hensley, R. T.

    2017-12-01

    Riverine processing of nutrients and carbon is a local process, subject to heterogeneity in sediment, biotic, insolation, and flow velocity drivers. Measurements at the reach scale aggregate across riverscapes, limiting their utility for enumerating these drivers, and thus for scaling to river networks. Using a combination of in situ sensors that sample water chemistry at high temporal resolution and open benthic chambers that isolate the biogeochemical impacts of a small footprint of benthic surface area, we explored controls on metabolism and nutrient cycling. We specifically sought to answer two questions. First, what are the controls on primary production, with a particular emphasis on the relative roles of light vs. nutrient limitation? Second, what are the pathways of nutrient retention, and do the reaction kinetics of these different pathways differ? We demonstrate the considerable utility of these benthic chambers, reasoning that they provide experimental units for river processes that are not attainable at the reach or network scale. Specifically, in addition to their ability to sample the heterogeneity of the river bed as well as observe nutrient depletion to create concentrations well below ambient levels, they enable manipulative experiments (e.g., nutrient enrichment, light reduction, grazer adjustments) while retaining key elements of the natural system. Across several of Florida's spring-fed river sites, our results strongly support the primacy of light limitation of primary production, with very little evidence of any incremental effects of nutrient enrichment. Nutrient depletion assays further support the dominance of two N retention mechanisms (denitrification and assimilation), the kinetics of which differ markedly, with denitrification exhibiting nearly first-order reactions, and assimilation following zero-order or Michaelis-Menten kinetics over the range of observed concentrations. This latter result helps explain the absence of strong

  4. Atmospheric deposition as a source of carbon and nutrients to barren, alpine soils of the Colorado Rocky Mountains

    Science.gov (United States)

    Mladenov, N.; Williams, M. W.; Schmidt, S. K.; Cawley, K.

    2012-03-01

    Many alpine areas are experiencing intense deglaciation, biogeochemical changes driven by temperature rise, and changes in atmospheric deposition. There is mounting evidence that the water quality of alpine streams may be related to these changes, including rising atmospheric deposition of carbon (C) and nutrients. Given that barren alpine soils can be severely C limited, we evaluated the magnitude and chemical quality of atmospheric deposition of C and nutrients to an alpine site, the Green Lake 4 catchment in the Colorado Rocky Mountains. Using a long term dataset (2002-2010) of weekly atmospheric wet deposition and snowpack chemistry, we found that volume weighted mean dissolved organic carbon (DOC) concentrations were approximately 1.0 mg L-1and weekly concentrations reached peaks as high at 6-10 mg L-1 every summer. Total dissolved nitrogen concentration also peaked in the summer, whereas total dissolved phosphorus and calcium concentrations were highest in the spring. Relationships among DOC concentration, dissolved organic matter (DOM) fluorescence properties, and nitrate and sulfate concentrations suggest that pollutants from nearby urban and agricultural sources and organic aerosols derived from sub-alpine vegetation may influence high summer DOC wet deposition concentrations. Interestingly, high DOC concentrations were also recorded during "dust-in-snow" events in the spring. Detailed chemical and spectroscopic analyses conducted for samples collected in 2010 revealed that the DOM in many late spring and summer samples was less aromatic and polydisperse and of lower molecular weight than that of winter and fall samples and, therefore, likely to be more bioavailable to microbes in barren alpine soils. Bioavailability experiments with different types of atmospheric C sources are needed to better evaluate the substrate quality of atmospheric C inputs. Our C budget estimates for the Green Lake 4 catchment suggest that atmospheric deposition represents an

  5. Presence and patterns of alkaline phosphatase activity and phosphorus cycling in natural riparian zones under changing nutrient conditions

    Directory of Open Access Journals (Sweden)

    Peifang Wang

    2014-08-01

    Full Text Available Phosphorus (P is an important limiting nutrient in aquatic ecosystems and knowledge of P cycling is fundamental for reducing harmful algae blooms and other negative effects in water. Despite their importance, the characteristics of P cycling under changing nutrient conditions in shallow lakes were poorly investigated. In this study, in situ incubation experiments were conducted in a natural riparian zone in the main diversion channel used for water transfer into Lake Taihu (Wangyu River. Variations in microbial biomass, dissolved P fractions (organic and inorganic, and alkaline phosphatase activity (bulk APA and specific APA were determined after incubation with and without the addition of P and nitrogen (N (4 total water treatments: +P, +N, +NP, and control. Experiments were conducted during two seasons (late spring and early fall to account for natural differences in nutrient levels that may occur in situ. Our results demonstrated that low levels of DRP may not necessarily indicate P limitation. Phytoplankton exhibited “serial N limitation with P stress” in May, such that chlorophyll a (Chl a increased significantly with N addition, while the limiting nutrient shifted to P in October and phytoplankton biomass increased with P addition. Phytoplankton contributed greatly to APA production and was significantly influenced by P bioavailability, yet high levels of bulk APA were also not necessarily indicative of P limitation. In contrast to phytoplankton, bacteria were less P stressed. As a consequence of enhanced utilization of dissolved reactive P (DRP and dissolved organic P (DOP, +N treatment elevated APA significantly. By contrast, APA could be repressed to low values and phytoplankton converted a large portion of DRP to DOP with P addition. But this was not consistent with bacteria APA (bact-APA in the absence or presence of abundant phytoplankton biomass. The correlation between bulk APA and DRP was good at separate sites and discrepant

  6. Solution and vapour deposited lead perovskite solar cells: Ecotoxicity from a life cycle assessment perspective

    DEFF Research Database (Denmark)

    Espinosa Martinez, Nieves; Serrano-Luján, Lucía; Urbina, Antonio

    2015-01-01

    We present a life cycle analysis (LCA) and an environmental impact analysis (EIA) of lead based perovskite solar cells prepared according to the two most successfully reported literature methods that comprise either vapour phase deposition or solution phase deposition. We have developed the inven......We present a life cycle analysis (LCA) and an environmental impact analysis (EIA) of lead based perovskite solar cells prepared according to the two most successfully reported literature methods that comprise either vapour phase deposition or solution phase deposition. We have developed...... the inventory for all the components employed for the two different device architectures that resemble respectively a traditional dye sensitised solar cell (DSSC) and an inverted polymer solar cell (OPV). We analyse the impacts from generation of 1 kWh of electricity and assume a lifetime of 1 year...... lead(II)halides is very limited compared to methylammoniumhalides employed. This applies during the raw materials extraction, synthesis of the starting materials and manufacture of the perovskite solar cells and from these points of view the lead based perovskite solar cells do not pose extra concerns...

  7. Effects of nitrogen deposition on carbon cycle in terrestrial ecosystems of China: A meta-analysis.

    Science.gov (United States)

    Chen, Hao; Li, Dejun; Gurmesa, Geshere A; Yu, Guirui; Li, Linghao; Zhang, Wei; Fang, Huajun; Mo, Jiangming

    2015-11-01

    Nitrogen (N) deposition in China has increased greatly, but the general impact of elevated N deposition on carbon (C) dynamics in Chinese terrestrial ecosystems is not well documented. In this study we used a meta-analysis method to compile 88 studies on the effects of N deposition C cycling on Chinese terrestrial ecosystems. Our results showed that N addition did not change soil C pools but increased above-ground plant C pool. A large decrease in below-ground plant C pool was observed. Our result also showed that the impacts of N addition on ecosystem C dynamics depend on ecosystem type and rate of N addition. Overall, our findings suggest that 1) decreased below-ground plant C pool may limit long-term soil C sequestration; and 2) it is better to treat N-rich and N-limited ecosystems differently in modeling effects of N deposition on ecosystem C cycle. Copyright © 2015 Elsevier Ltd. All rights reserved.

  8. The influence of continental air masses on the aerosols and nutrients deposition over the western North Pacific

    Science.gov (United States)

    Fu, Jiangping; Wang, Bo; Chen, Ying; Ma, Qingwei

    2018-01-01

    The air masses transported from East Asia have a strong impact on the aerosol properties and deposition in the marine boundary layer of the western North Pacific (WNP) during winter and spring. We joined a cruise between 17 Mar. and 22 Apr. 2014 and investigated the changes of aerosol composition and size distribution over the remote WNP and marginal seas. Although the secondary aerosol species (SO42-, NO3- and NH4+) in remote WNP were influenced significantly by the continental transport, NH4+ concentrations were lower than 2.7 μg m-3 in most sampling days and not correlated with non-sea-salt (nss)-SO42- suggesting that the ocean could be a primary source of NH4+. Moderate Cl- depletion (23%) was observed in remote WNP, and the inverse relationship between Cl- depletion percentages and nss-K+ in aerosols suggested that the transport of biomass burning smoke from East Asia might be a vital extra source of Cl-. Both Asian dust and haze events were encountered during the cruise. Asian dust carried large amounts of crustal elements such as Al and Ti to the WNP, and the dusty Fe deposition may double its background concentration in seawater. Differently, a dramatic increase of dry deposition flux of dissolved particulate inorganic nitrogen was observed during the haze event. Our study reveals that the transport of different continental air masses may have distinct biogeochemical impacts on the WNP by increasing the fluxes of different nutrient elements and potentially changing the nutrient stoichiometry.

  9. Design and construction of a vertical hydroponic system with semi-continuous and continuous nutrient cycling

    Science.gov (United States)

    Siswanto, Dian; Widoretno, Wahyu

    2017-11-01

    Problems due to the increase in agricultural land use change can be solved by hydroponic system applications. Many hydroponic studies have been conducted in several countries while their applications in Indonesia requires modification and adjustment. This research was conducted to design and construct a hydroponic system with semi-continuous and continuous nutrition systems. The hydroponic system which was used adapts the ebb and flow system, and the nutrient film technique (NFT). This hydroponic system was made from polyvinyl chloride (PVC) pipes with a length of 197 cm, a diameter of 16 cm, and a slope of 4°. It was constructed from four PVC pipes. In semi-continuous irrigation treatment, nutrients flow four to six times for each of ten minutes depending on plant development and the estimated evapotranspiration occurring, while in a continuous nutrient system the nutrients are streamed for twenty-four hours without stopping at a maximum flow rate of 13.7 L per second.

  10. Nitrogen and sulfur deposition and forest nutrient status in the Valley of Mexico

    Science.gov (United States)

    M. E. Fenn; L. I. de Bauer; A. Quevedo-Nolasco; Rodriquez-Frausto-C.

    1999-01-01

    Mexico City experiences some of the most severe air pollution in the world. Ozone injury has been documented in sensitive tree species in urban and forested areas in the Valley of Mexico. However, little is known of the levels of other atmospheric pollutants and their ecological effects on forests in the Valley of Mexico. In this study bulk throughfall deposition of...

  11. The effect of nutrient deposition on bacterial communities in Arctic tundra soil

    Science.gov (United States)

    Barbara J. Campbell; Shawn W. Polson; Thomas E. Hanson; Michelle C. Mack; Edward A.G. Schuur

    2010-01-01

    The microbial communities of high-latitude ecosystems are expected to experience rapid changes over the next century due to climate warming and increased deposition of reactive nitrogen, changes that will likely affect microbial community structure and function. In moist acidic tundra (MAT) soils on the North Slope of the Brooks Range, Alaska, substantial losses of C...

  12. Nutrient cycling for biomass: Interactive proteomic/transcriptomic networks for global carbon management processes within poplar-mycorrhizal interactions

    Energy Technology Data Exchange (ETDEWEB)

    Cseke, Leland [Univ. of Alabama, Huntsville, AL (United States)

    2016-08-30

    free living conditions. Together, the assembled team of experts completed all of the planned milestones set forth in this project. In addition to the planned approaches, several lines of exciting new research have also evolved during the course of this project that involved FTIR Imaging using the National Synchrotron Light Source at BNL. A summary of the approaches used in this project and key highlights are as follows: Having the right combination of microbes associated with plants is largely responsible for the plant’s ability to mine nutrients from the soil and to develop a strong “immune system”. Our current chemically focused and intensive culture tends to forget that plants obtain nutrients in two ways: (1) via water soluble chemical nutrients and (2) via the activity of acquired microbial symbionts. In healthy natural ecosystems, chemical nutrients are always in low abundance because the organisms within that system have already locked such nutrients away within the biological system itself. Thus, in nature it is the biological sources of nutrients and the microbes that have the capacity to mine those nutrients for their plant hosts that actually control the terrestrial nutrient cycles on this planet. Thus, a new push in the future may very well be to use our skills at elucidating complex patterns to strategically guide soil microbe communities to do what we want, essentially allowing nature to do the work of figuring out what is most efficient and effective for human needs. However, the findings of this project and other work in our lab lead to the hypothesis that the specific soil community composition is less important than the emergent properties of those communities. So, additional research into what soil communities are effective and how they are established will be key in developing human understanding of how to manipulate biological systems to meet human needs without causing undue damage to our environment.

  13. Nitrogen deposition alters nitrogen cycling and reduces soil carbon content in low-productivity semiarid Mediterranean ecosystems

    International Nuclear Information System (INIS)

    Ochoa-Hueso, Raúl; Maestre, Fernando T.; Ríos, Asunción de los; Valea, Sergio; Theobald, Mark R.; Vivanco, Marta G.; Manrique, Esteban; Bowker, Mathew A.

    2013-01-01

    Anthropogenic N deposition poses a threat to European Mediterranean ecosystems. We combined data from an extant N deposition gradient (4.3–7.3 kg N ha −1 yr −1 ) from semiarid areas of Spain and a field experiment in central Spain to evaluate N deposition effects on soil fertility, function and cyanobacteria community. Soil organic N did not increase along the extant gradient. Nitrogen fixation decreased along existing and experimental N deposition gradients, a result possibly related to compositional shifts in soil cyanobacteria community. Net ammonification and nitrification (which dominated N-mineralization) were reduced and increased, respectively, by N fertilization, suggesting alterations in the N cycle. Soil organic C content, C:N ratios and the activity of β-glucosidase decreased along the extant gradient in most locations. Our results suggest that semiarid soils in low-productivity sites are unable to store additional N inputs, and that are also unable to mitigate increasing C emissions when experiencing increased N deposition. -- Highlights: •Soil organic N does not increase along the extant N deposition gradient. •Reduced N fixation is related to compositional shifts in soil cyanobacteria community. •Nitrogen cycling is altered by simulated N deposition. •Soil organic C content decrease along the extant N deposition gradient. •Semiarid soils are unable to mitigate CO 2 emissions after increased N deposition. -- N deposition alters N cycling and reduces soil C content in semiarid Mediterranean ecosystems

  14. Closing the Global Energy and Nutrient Cycles through Application of Biogas Residue to Agricultural Land – Potential Benefits and Drawback

    Directory of Open Access Journals (Sweden)

    Veronica Arthurson

    2009-04-01

    Full Text Available Anaerobic digestion is an optimal way to treat organic waste matter, resulting in biogas and residue. Utilization of the residue as a crop fertilizer should enhance crop yield and soil fertility, promoting closure of the global energy and nutrient cycles. Consequently, the requirement for production of inorganic fertilizers will decrease, in turn saving significant amounts of energy, reducing greenhouse gas emissions to the atmosphere, and indirectly leading to global economic benefits. However, application of this residue to agricultural land requires careful monitoring to detect amendments in soil quality at the early stages.

  15. Loess deposits in Beijing and their paleoclimatic implications during the last interglacial-glacial cycle

    Science.gov (United States)

    Tian, Shengchen; Sun, Jimin; Gong, Zhijun

    2017-12-01

    Loess-paleosol sequences are important terrestrial paleoclimatic archives in the semi-arid region of north-central China. Compared with the numerous studies on the loess of the Chinese Loess Plateau, the eolian deposits, near Beijing, have not been well studied. A new loess section in the northeast suburb of Beijing provides an opportunity for reconstructing paleoenvironmental changes in this region. An optically stimulated luminescence (OSL) chronology yields ages of 145.1 to 20.5 ka, demonstrating that the loess deposits accumulated during the last interglacial-glacial cycle. High-resolution climatic proxies, including color-index, particle size and magnetic parameters, reveal orbital-scale climatic cycles, corresponding to marine oxygen isotope stages (MIS) 6 to MIS 2. In contrast to the loess deposits of the central Loess Plateau, loess near Beijing is a mixture of distal dust materials from gobi and sand deserts in the arid part of northwestern China and proximal, local alluvial sediments. Climatic change in Beijing during the last interglacial-glacial cycle was controlled primarily by the changing strength of the East Asian monsoon. Paleosols developed during the last interglacial complex (between 144.0 and 73.0 ka) and the interstadial of the last glaciation (between 44.6 and 36.2 ka), being associated with an enhanced summer monsoon in response to increased low-latitude insolation and a weakened Siberia High. Loess accumulation occurred during cold-dry stages of the last glaciation, in response to the intensified winter monsoon driven by the strengthened Siberia High and its longer residence time.

  16. Atmospheric deposition impacts on nutrients and biological budgets of the Mediterranean Sea, results from the high resolution coupled model NEMOMED12/PISCES

    Science.gov (United States)

    Richon, Camille; Dutay, Jean-Claude; Dulac, François; Desboeufs, Karine; Nabat, Pierre; Guieu, Cécile; Aumont, Olivier; Palmieri, Julien

    2016-04-01

    Atmospheric deposition is at present not included in regional oceanic biogeochemical models of the Mediterranean Sea, whereas, along with river inputs, it represents a significant source of nutrients at the basin scale, especially through intense desert dust events. Moreover, observations (e.g. DUNE campaign, Guieu et al. 2010) show that these events significantly modify the biogeochemistry of the oligotrophic Mediterranean Sea. We use a high resolution (1/12°) version of the 3D coupled model NEMOMED12/PISCES to investigate the effects of high resolution atmospheric dust deposition forcings on the biogeochemistry of the Mediterranean basin. The biogeochemical model PISCES represents the evolution of 24 prognostic tracers including five nutrients (nitrate, ammonium, phosphate, silicate and iron) and two phytoplankton and zooplanktons groups (Palmiéri, 2014). From decadal simulations (1982-2012) we evaluate the influence of natural dust and anthropogenic nitrogen deposition on the budget of nutrients in the basin and its impact on the biogeochemistry (primary production, plankton distributions...). Our results show that natural dust deposition accounts for 15% of global PO4 budget and that it influences primarily the southern part of the basin. Anthropogenic nitrogen accounts for 50% of bioavailable N supply for the northern part. Deposition events significantly affect biological production; primary productivity enhancement can be as high as 30% in the areas of high deposition, especially during the stratified period. Further developments of the model will include 0D and 1D modeling of bacteria in the frame of the PEACETIME project.

  17. Effects of increased deposition of atmospheric nitrogen on an upland moor: Nitrogen budgets and nutrient accumulation

    International Nuclear Information System (INIS)

    Pilkington, M.G.; Caporn, S.J.M.; Carroll, J.A.; Cresswell, N.; Lee, J.A.; Reynolds, B.; Emmett, B.A.

    2005-01-01

    This study was designed to investigate the effect of long-term (11 years) ammonium nitrate additions on standing mass, nutrient content (% and kg ha -1 ), and the proportion of the added N retained within the different compartments of the system. The results showed that more than 90% of all N in the system was found in the soil, particularly in the organic (Oh) horizon. Added N increased the standing mass of vegetation and litter and the N content (kg N ha -1 ) of almost all measured plant, litter and soil compartments. Green tissue P and K content (kg ha -1 ) were increased, and N:P ratios were increased to levels indicative of P limitation. At the lowest treatment, most of the additional N was found in plant/litter compartments, but at higher treatments, there were steep increases in the amount of additional N in the underlying organic and mineral (Eag) horizons. The budget revealed that the proportion of added N found in the system as a whole increased from 60%, 80% and up to 90% in response to the 40, 80 and 120 kg N ha -1 year -1 treatments, respectively. - Additions of 40 kg N ha -1 over 11 years accumulated mainly in plant and litter compartments; higher additions accumulated mainly in the organic and mineral horizons

  18. Biogeochemical characterization of the Cointzio reservoir (Morelia, Mexico) and identification of a watershed-dependent cycling of nutrients

    Science.gov (United States)

    Némery, J.; Alvarado, R.; Gratiot, N.; Duvert, C.; Mahé, F.; Duwig, C.; Bonnet, M.; Prat, C.; Esteves, M.

    2009-12-01

    The Cointzio reservoir (capacity 70 Mm3) is an essential component of the drinking water supply (20 %) of Morelia city (1 M inhabitants, Michoacán, Mexico). The watershed is 627 km2 and mainly forested (45 %) and cultivated (43 %) with recent increase of avocados plantations. The mean population density is 65 inh./km2 and there are no waste water treatment plants in the villages leading locally to high levels of organic and nutritive pollution. Soils are mostly volcanic and recent deforestations have led to important processes of erosion especially during the wet season (from June to October). As a result the reservoir presents a high turbidity level (Secchi Del Agua (CNA). The water residence time in the reservoir is lower than one year. Nutrients fluxes entering and exiting the reservoir were calculated as the product of water discharges and weekly concentrations of nutrients. Within the reservoir, the vertical distributions of temperature, oxygen, turbidity, pH (with a Hydrolab probe), nutrients (PO43-, NH4+, NO3-), Dissolved Organic Carbon, chlorophyll a (laboratory analysis with a Hach Lange spectrophotometer), phytoplankton and zooplankton (variety and abundance) were measured every month to determine its seasonal dynamics. Samples of deposited sediments were also taken to assess phosphorus (P) stock. Nutrient inputs revealed to be strongly conditioned by the watershed hydrology. During low flow period (November to May), the baseflow is much more concentrated in dissolved nutrients. On the contrary, the high flows (June to October) bring a high amount of suspended sediments (up to 50g/L) that transport nutrients such as particulate P. Despite the high turbidity level of the reservoir, chlorophyll a concentrations appear important (70 µg/L during the dry season) especially in the first five meters of the water column. The phytoplankton community is dominated by Euglenophyta and Cyanobacteria groups typical of eutrophic waters. This study is the first

  19. Life cycle comparison of centralized wastewater treatment and urine source separation with struvite precipitation: Focus on urine nutrient management.

    Science.gov (United States)

    Ishii, Stephanie K L; Boyer, Treavor H

    2015-08-01

    Alternative approaches to wastewater management including urine source separation have the potential to simultaneously improve multiple aspects of wastewater treatment, including reduced use of potable water for waste conveyance and improved contaminant removal, especially nutrients. In order to pursue such radical changes, system-level evaluations of urine source separation in community contexts are required. The focus of this life cycle assessment (LCA) is managing nutrients from urine produced in a residential setting with urine source separation and struvite precipitation, as compared with a centralized wastewater treatment approach. The life cycle impacts evaluated in this study pertain to construction of the urine source separation system and operation of drinking water treatment, decentralized urine treatment, and centralized wastewater treatment. System boundaries include fertilizer offsets resulting from the production of urine based struvite fertilizer. As calculated by the Tool for the Reduction and Assessment of Chemical and Other Environmental Impacts (TRACI), urine source separation with MgO addition for subsequent struvite precipitation with high P recovery (Scenario B) has the smallest environmental cost relative to existing centralized wastewater treatment (Scenario A) and urine source separation with MgO and Na3PO4 addition for subsequent struvite precipitation with concurrent high P and N recovery (Scenario C). Preliminary economic evaluations show that the three urine management scenarios are relatively equal on a monetary basis (<13% difference). The impacts of each urine management scenario are most sensitive to the assumed urine composition, the selected urine storage time, and the assumed electricity required to treat influent urine and toilet water used to convey urine at the centralized wastewater treatment plant. The importance of full nutrient recovery from urine in combination with the substantial chemical inputs required for N recovery

  20. Nutrient limitation in three lowland tropical forests in southern China receiving high nitrogen deposition: insights from fine root responses to nutrient additions.

    Science.gov (United States)

    Zhu, Feifei; Yoh, Muneoki; Gilliam, Frank S; Lu, Xiankai; Mo, Jiangming

    2013-01-01

    Elevated nitrogen (N) deposition to tropical forests may accelerate ecosystem phosphorus (P) limitation. This study examined responses of fine root biomass, nutrient concentrations, and acid phosphatase activity (APA) of bulk soil to five years of N and P additions in one old-growth and two younger lowland tropical forests in southern China. The old-growth forest had higher N capital than the two younger forests from long-term N accumulation. From February 2007 to July 2012, four experimental treatments were established at the following levels: Control, N-addition (150 kg N ha(-1) yr(-1)), P-addition (150 kg P ha(-1) yr(-1)) and N+P-addition (150 kg N ha(-1) yr(-1) plus 150 kg P ha(-1) yr(-1)). We hypothesized that fine root growth in the N-rich old-growth forest would be limited by P availability, and in the two younger forests would primarily respond to N additions due to large plant N demand. Results showed that five years of N addition significantly decreased live fine root biomass only in the old-growth forest (by 31%), but significantly elevated dead fine root biomass in all the three forests (by 64% to 101%), causing decreased live fine root proportion in the old-growth and the pine forests. P addition significantly increased live fine root biomass in all three forests (by 20% to 76%). The combined N and P treatment significantly increased live fine root biomass in the two younger forests but not in the old-growth forest. These results suggest that fine root growth in all three study forests appeared to be P-limited. This was further confirmed by current status of fine root N:P ratios, APA in bulk soil, and their responses to N and P treatments. Moreover, N addition significantly increased APA only in the old-growth forest, consistent with the conclusion that the old-growth forest was more P-limited than the younger forests.

  1. Optimal Management of Water, Nutrient and Carbon Cycles of Green Urban Spaces

    Science.gov (United States)

    Revelli, R.; Pelak, N. F., III; Porporato, A. M.

    2016-12-01

    The urban ecosystem is a complex, metastable system with highly coupled flows of mass, energy, people and capital. Their sustainability is in part linked to the existence of green spaces which provide important ecosystem services, whose sustainable management requires quantification of their benefits in terms of impacts on water, carbon and energy fluxes. An exploration of problems of optimal management of such green urban spaces and the related biogeochemical fluxes is presented, extending probabilistic ecohydrological models of the soil-plant system to the urban context, where biophysical and ecological conditions tend to be radically different from the surrounding rural and natural environment (e.g. heat islands, air and water pollution, low quality soils, etc…). The coupled soil moisture, nutrient and plant dynamics are modeled to compute water requirements, carbon footprint, nutrient demand and losses, and related fluxes under different design, management and climate scenarios. The goal is to provide operative rules for a sustainable water use through focused irrigation and fertilization strategies, optimal choice of plants, soil and cultivation conditions, accounting for the typical hydroclimatic variability that occur in the urban environment. This work is part of a project that has received funding from the European Union's Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant agreement No 701914. The work is also cofounded by USDA Agricultural Research Service cooperative agreement 58-6408-3-027; National Science Foundation (NSF) grants: EAR-1331846, EAR-1316258, and the DGE-1068871 and FESD EAR-1338694.

  2. Combined use of stable isotopes and hydrologic modeling to better understand nutrient sources and cycling in highly altered systems (Invited)

    Science.gov (United States)

    Young, M. B.; Kendall, C.; Guerin, M.; Stringfellow, W. T.; Silva, S. R.; Harter, T.; Parker, A.

    2013-12-01

    The Sacramento and San Joaquin Rivers provide the majority of freshwater for the San Francisco Bay Delta. Both rivers are important sources of drinking and irrigation water for California, and play critical roles in the health of California fisheries. Understanding the factors controlling water quality and primary productivity in these rivers and the Delta is essential for making sound economic and environmental water management decisions. However, these highly altered surface water systems present many challenges for water quality monitoring studies due to factors such as multiple potential nutrient and contaminant inputs, dynamic source water inputs, and changing flow regimes controlled by both natural and engineered conditions. The watersheds for both rivers contain areas of intensive agriculture along with many other land uses, and the Sacramento River receives significant amounts of treated wastewater from the large population around the City of Sacramento. We have used a multi-isotope approach combined with mass balance and hydrodynamic modeling in order to better understand the dominant nutrient sources for each of these rivers, and to track nutrient sources and cycling within the complex Delta region around the confluence of the rivers. High nitrate concentrations within the San Joaquin River fuel summer algal blooms, contributing to low dissolved oxygen conditions. High δ15N-NO3 values combined with the high nitrate concentrations suggest that animal manure is a significant source of nitrate to the San Joaquin River. In contrast, the Sacramento River has lower nitrate concentrations but elevated ammonium concentrations from wastewater discharge. Downstream nitrification of the ammonium can be clearly traced using δ15N-NH4. Flow conditions for these rivers and the Delta have strong seasonal and inter-annual variations, resulting in significant changes in nutrient delivery and cycling. Isotopic measurements and estimates of source water contributions

  3. Bioaerosols in the Eastern Mediterranean: abundance, speciation, seasonality, impact on nutrient cycles and role of airmass and meteorology

    Science.gov (United States)

    Almpani, Chara; Negron, Arnaldo; Kanakidou, Maria; Mihalopoulos, Nikolaos; Nenes, Athanasios

    2017-04-01

    Primary biological aerosol particles (PBAPs) are a ubiquitous component of the atmosphere. They are studied in part to understand their unique role in cloud formation by acting as cloud condensation nuclei (CCN) and ice nuclei (IN) [1, 2], impacts on health and their role as nutrient supply for ocean ecosystems [3]. Little is known about the seasonal variability, lifecycle and survival mechanism in the atmosphere of PBAPs, in part due to challenges in available techniques for their detection. Our study aims to quantify the concentration of supermicron PBAPs at a remote marine ground site in the Eastern Mediterranean to help understand their potential impacts on cloud formation, and contribution to nutrient deposition to the surface ocean. Sampling took place in the Finokalia Station and in the city of Heraklion. Eight hour samples were collected using a Spincon II wet-walled cyclone sampler every two days over a 9-month period (May, 2016 - January 2017) and were subsequently analyzed using flow cytometry and epifluorescence microscopy protocols developed by Negron et al., 2017 [4]. Preliminary results show low biomass samples over Finokalia site and concentrations around 103 - 105 m-3, depending on the origin of the airmass. Further analysis of the samples focus on the influence of meteorological conditions on the relative abundance of bacteria, fungi, pollen, associated virues and biological debris. Estimates of the nutrient fluxes and the seasonality thereof are also provided, and compared against existing modeling estimates [3]. References: [1] Jaenicke, R. Science 308, 73. [2] Morris, C. E. et al., Glob Chang Biol 20(2): 341-351. [3] Myriokefalitakis et al., Biogeosciences, 13, 6519-6543 [4] Negron, A., et al., in preparation.

  4. How do persistent organic pollutants be coupled with biogeochemical cycles of carbon and nutrients in terrestrial ecosystems under global climate change?

    Energy Technology Data Exchange (ETDEWEB)

    Teng, Ying [Chinese Academy of Sciences, Nanjing (China). Key Lab. of Soil Environment and Pollution Remediation; Griffith Univ., Nathan, QLD (Australia). Environmetnal Futures Centre and School of Biomolecular and Physical Sciences; Xu, Zhihong; Reverchon, Frederique [Griffith Univ., Nathan, QLD (Australia). Environmetnal Futures Centre and School of Biomolecular and Physical Sciences; Luo, Yongming [Chinese Academy of Sciences, Nanjing (China). Key Lab. of Soil Environment and Pollution Remediation

    2012-03-15

    Global climate change (GCC), especially global warming, has affected the material cycling (e.g., carbon, nutrients, and organic chemicals) and the energy flows of terrestrial ecosystems. Persistent organic pollutants (POPs) were regarded as anthropogenic organic carbon (OC) source, and be coupled with the natural carbon (C) and nutrient biogeochemical cycling in ecosystems. The objective of this work was to review the current literature and explore potential coupling processes and mechanisms between POPs and biogeochemical cycles of C and nutrients in terrestrial ecosystems induced by global warming. Global warming has caused many physical, chemical, and biological changes in terrestrial ecosystems. POPs environmental fate in these ecosystems is controlled mainly by temperature and biogeochemical processes. Global warming may accelerate the re-emissions and redistribution of POPs among environmental compartments via soil-air exchange. Soil-air exchange is a key process controlling the fate and transportation of POPs and terrestrial ecosystem C at regional and global scales. Soil respiration is one of the largest terrestrial C flux induced by microbe and plant metabolism, which can affect POPs biotransformation in terrestrial ecosystems. Carbon flow through food web structure also may have important consequences for the biomagnification of POPs in the ecosystems and further lead to biodiversity loss induced by climate change and POPs pollution stress. Moreover, the integrated techniques and biological adaptation strategy help to fully explore the coupling mechanisms, functioning and trends of POPs and C and nutrient biogeochemical cycling processes in terrestrial ecosystems. There is increasing evidence that the environmental fate of POPs has been linked with biogeochemical cycles of C and nutrients in terrestrial ecosystems under GCC. However, the relationships between POPs and the biogeochemical cycles of C and nutrients are still not well understood. Further

  5. Biological impacts of alcohol fuel emission on selected pollinator, predatory and nutrient-cycling insects and arachnids

    Energy Technology Data Exchange (ETDEWEB)

    D' Eliscu, P.N.

    1981-01-01

    Physiological and behavioral effects of methanol, ethanol, indolene, and formaldehyde emissions on selected arthropods are related to different relative organismic activities, metabolic rates, and respiratory demands. Various species of important pollinators, predators, and nutrient-cycling insects and arachnids respond differently to tailpipe and elevated levels of emissions. A gradient of responses is related to metabolism and trophic niche. Orders tested included various Hymenoptera, Diptera, Lepidoptera, Odonata, Orthoptera, Coleoptera, Collembola, Thysanura, Araneae, Acarina, and Opiliones. Responses included narcosis, spatial disorientation, cardiac arrhythmia, flight muscle and walking leg dysfunction, decreased feeding efficiency and prey capture success ratios, and increased positive thigmotaxis. Tolerance appears to be inversely related to oxygen demand of the arthropods tested, with active fliers most susceptible, weak fliers midscale, and non-fliers most tolerant. Electronic monitoring of heart, brain, and muscle characteristics suggests neuronal and neurosynaps disruptions from alcohols and formaldehyde, and neuromuscular effects from indolene in most arthropods tested.

  6. The role of the Everglades Mangrove Ecotone Region (EMER) in regulating nutrient cycling and wetland productivity in South Florida

    Science.gov (United States)

    Rivera-Monroy, Victor H.; Twilley, Robert R.; Davis, Stephen E.; Childers, Daniel L.; Simard, Marc; Chambers, Randolph; Jaffe, Rudolf; Boyer, Joseph N.; Rudnick, David T.; Zhang, Keqi; Castañeda-Moya, Edward; Ewe, Sharon M.L.; Price, Rene M.; Coronado-Molina, Carlos; Ross, Michael; Smith, Thomas J.; Michot, Beatrice; Meselhe, Ehab; Nuttle, William; Troxler, Tiffany G.; Noe, Gregory B.

    2011-01-01

    The authors summarize the main findings of the Florida Coastal Everglades Long-Term Ecological Research (FCE-LTER) program in the EMER, within the context of the Comprehensive Everglades Restoration Plan (CERP), to understand how regional processes, mediated by water flow, control population and ecosystem dynamics across the EMER landscape. Tree canopies with maximum height -1) in the calcareous marl substrate and long hydroperiod. Phosphorus limits the EMER and its freshwater watersheds due to the lack of terrigenous sediment input and the phosphorus-limited nature of the freshwater Everglades. Reduced freshwater delivery over the past 50 years, combined with Everglades compartmentalization and a 10 cm rise in coastal sea level, has led to the landward transgression (~1.5 km in 54 years) of the mangrove ecotone. Seasonal variation in freshwater input strongly controls the temporal variation of nitrogen and P exports (99%) from the Everglades to Florida Bay. Rapid changes in nutrient availability and vegetation distribution during the last 50 years show that future ecosystem restoration actions and land use decisions can exert a major influence, similar to sea level rise over the short term, on nutrient cycling and wetland productivity in the EMER.

  7. Silicon isotope fractionation between rice plants and nutrient solution and its significance to the study of the silicon cycle

    Science.gov (United States)

    Ding, T. P.; Tian, S. H.; Sun, L.; Wu, L. H.; Zhou, J. X.; Chen, Z. Y.

    2008-12-01

    solutions. The calculated silicon isotope fractionation factor between the silicon instantaneously absorbed by rice roots and the silicon in nutrient solution vary from 0.9983 at start to 0.9995 at harvest, similar to those reported for bamboo, banana and diatoms in direction and extent. In the maturity stage, the δ30Si value of rice organs decreased from -1.33‰ in roots to -1.98‰ in stem, and then increased through -0.16‰ in leaves and 1.24‰ in husks, to 2.21‰ in grains. This trend is similar to those observed in the field grown rice and bamboo. These quantitative data provide us a solid base for understanding the mechanisms of silicon absorption, transportation and precipitation in rice plants and the role of rice growth in the continental Si cycle.

  8. Nutrient- and Climate-Induced Shifts in the Phenology of Linked Biogeochemical Cycles in a Temperate Estuary

    Directory of Open Access Journals (Sweden)

    Jeremy M. Testa

    2018-04-01

    Full Text Available The response of estuarine ecosystems to long-term changes in external forcing is strongly mediated by interactions between the biogeochemical cycling of carbon, oxygen, and inorganic nutrients. Although long-term changes in estuaries are often assessed at the annual scale, phytoplankton biomass, dissolved oxygen concentrations, and biogeochemical rate processes have strong seasonal cycles at temperate latitudes. Thus, changes in the seasonal timing, or phenology, of these key processes can reveal important features of long-term change and help clarify the nature of coupling between carbon, oxygen, and nutrient cycles. Changes in the phenology of estuarine processes may be difficult to assess, however, because many organisms are mobile and migratory, key primary and secondary producers have relatively rapid physiological turnover rates, sampling in time and space is often limited, and physical processes may dominate variability. To overcome these challenges, we have analyzed a 32-year record (1985–2016 of relatively frequent and consistent measurements of chlorophyll-a, dissolved oxygen, nitrogen, and physical drivers to understand long-term change in Chesapeake Bay. Using a suite of metrics that directly test for altered phenology, we quantified changes in the seasonal timing of key biogeochemical events, which allowed us to illustrate spatially- and seasonally-dependent shifts in the magnitude of linked biogeochemical parameters. Specifically, we found that a modest reduction in nitrate input was linked to a suppression of spring phytoplankton biomass in seaward Bay regions. This was, in turn, associated with an earlier breakup in hypoxia and decline in late-summer NH4+ accumulation in seaward waters. In contrast, we observed an increase in winter phytoplankton biomass in landward regions, which was associated with elevated early summer hypoxic volumes and NH4+ accumulation. Seasonal shifts in oxygen depletion and NH4+ accumulation are

  9. Iron-dependent nitrogen cycling in a ferruginous lake and the nutrient status of Proterozoic oceans

    DEFF Research Database (Denmark)

    Michiels, Céline C.; Darchambeau, Francois; Roland, Fleur A. E.

    2017-01-01

    Nitrogen limitation during the Proterozoic has been inferred from the great expanse of ocean anoxia under low-O2 atmospheres, which could have romoted NO3-reduction to N2 and fixed N loss from the ocean. The deep oceans were Fe rich (ferruginous) during much of this time, yet the dynamics of N...... cycling under such conditions remain entirely conceptual, as analogue environments are rare today. Here we use incubation experiments to show that a modern ferruginous basin, Kabuno Bay in East Africa, supports high rates of NO3- reduction. Although 60% of this NO3- is reduced to N2 through canonical...

  10. Cancer cell metabolism and mitochondria: Nutrient plasticity for TCA cycle fueling.

    Science.gov (United States)

    Corbet, Cyril; Feron, Olivier

    2017-08-01

    Warburg's hypothesis that cancer cells take up a lot of glucose in the presence of ambient oxygen but convert pyruvate into lactate due to impaired mitochondrial function led to the misconception that cancer cells rely on glycolysis as their major source of energy. Most recent 13 C-based metabolomic studies, including in cancer patients, indicate that cancer cells may also fully oxidize glucose. In addition to glucose-derived pyruvate, lactate, fatty acids and amino acids supply substrates to the TCA cycle to sustain mitochondrial metabolism. Here, we discuss how the metabolic flexibility afforded by these multiple mitochondrial inputs allows cancer cells to adapt according to the availability of the different fuels and the microenvironmental conditions such as hypoxia and acidosis. In particular, we focused on the role of the TCA cycle in interconnecting numerous metabolic routes in order to highlight metabolic vulnerabilities that represent attractive targets for a new generation of anticancer drugs. Copyright © 2017 Elsevier B.V. All rights reserved.

  11. The Changing Seasonality of Tundra Nutrient Cycling: Implications for Arctic Ecosystem Function

    Science.gov (United States)

    Weintraub, M. N.; Steltzer, H.; Sullivan, P.; Schimel, J.; Wallenstein, M. D.; Darrouzet-Nardi, A.; Segal, A. D.

    2011-12-01

    Arctic soils contain large stores of carbon (C) and may act as a significant CO2 source with warming. However, the key to understanding tundra soil processes is nitrogen (N), as both plant growth and decomposition are N limited. However, current models of tundra ecosystems assume that while N limits plant growth, C limits decomposition. In addition, N availability is strongly seasonal with relatively high concentrations early in the growing season followed by a pronounced crash. We need to understand the controls on this seasonality to predict responses to climate change, but there are multiple questions that need answers: 1) What causes the seasonality in N? 2) Does microbial activity switch seasonally between C and N limitation? 3) How will a lengthening of the growing season alter overall ecosystem C and N dynamics, as a result of differential extension of the periods before and after the nutrient crash? We hypothesized that microbial activity is C limited early in the growing season, when N availability is higher and root exudate C is unavailable, and that microbial activity becomes N limited in response to plant N uptake and immobilization stimulated by root C. To address these questions we are conducting an accelerated snow-melt X warming field experiment in an Alaskan moist acidic arctic tundra community, and following plant and soil dynamics. Changes in the timing of C and N interactions in the different treatments will enable us to develop an enhanced mechanistic understanding of why the nutrient crash occurs and what the implications are for a lengthening of the arctic growing season. In 2010 we successfully accelerated snowmelt by 4 days. Both earlier snowmelt and warming accelerated early season plant life history events, with a few exceptions. However, responses to the combined treatment could not always be predicted from single factor effects. End of season life history events occurred later in response to the treatments, again with a few exceptions

  12. Atmospheric bulk deposition to the lagoon of Venice Part I. Fluxes of metals, nutrients and organic contaminants.

    Science.gov (United States)

    Rossini, P; Guerzoni, S; Molinaroli, E; Rampazzo, G; De Lazzari, A; Zancanaro, A

    2005-09-01

    First available data on atmospheric fall-out were provided by sampling monthly bulk depositions in four sites inside the Lagoon of Venice (550 km2). Sampling was carried out monthly during the period July 1998-July 1999, in one site near an industrial area (Porto Marghera; site D), another site in the city of Venice (site A), and the remaining two in the southern- and northernmost ends of the Lagoon (Valle Figheri, site C; Valle Dogà site B). The following determinations were carried out for each samples: pH, conductivity, grain-size, particulate load, and dissolved nutrients (N, P). Samples were then subdivided into soluble and insoluble fractions, and Al, Ca, Na, K, Mg, Si, Mn, Fe, Zn, Ni, Cr, Cu, Pb, Cd, As, Hg, Ti, V, S, P, Se and Sb were analysed on both fractions. Total organic micropollutants (PAH, PCB, HCB, DDT, PCDD/F) were measured. As regards particle size distribution, there was great variability among sampling sites. The percentage of the < or =2 microm grain-size fraction was higher in the southern and northern ends of the Lagoon. Small differences were found among sites for major elements, whereas higher variability was observed for inorganic and organic micropollutants, with standard deviations between 20% and 60% of the fluxes measured. Major differences in annual fluxes between the most polluted sites (mostly D and A) and background (site B) were seen for Cd (0.26 vs. 0.06 mg m(-2) year(-1)), Hg (41 vs. 15 microg m(-2) year(-1)), PCB ( approximately 2500 vs. approximately 500 ng m(-2) year(-1)) and HCB ( approximately 8000 vs. approximately 1000 ng m(-2) year(-1)). Comparisons with previous data, collected in the periods 1993-1994 and 1995-1997, were only available for a few trace metals. A definite decline in the annual Pb flux in the city of Venice was detected, from 18 to 13 mg m(-2) in 1996/1997 and 1995/1996 respectively, to approximately 5 mg m(-2) in the present study. Total annual deposition was calculated by means of two different

  13. Calcium oxalate contribution to calcium cycling in forests of contrasting nutrient status

    Science.gov (United States)

    Dauer, Jenny M.; Perakis, Steven S.

    2014-01-01

    Calcium oxalate (Ca oxalate) is an insoluble biomineral that forms in plants and fungi, and occurs in soils across many types of ecosystems. Assessing how Ca oxalate may shape ecosystem Ca cycling requires information on the distribution of Ca oxalate among plant biomass, detritus, and mineral soil, and how it varies with ecosystem Ca status. We compared two Douglas-fir forests of contrasting ecosystem Ca availability, and found that Ca oxalate was partitioned similarly among plant biomass, detritus and mineral soil major ecosystem compartments at both sites, and total pools of Ca oxalate were greater in the high-Ca forest. However, the proportional importance of Ca oxalate was greater in the low-Ca than high-Ca forest (18% versus 4% of actively cycling ecosystem Ca, respectively). And calcium oxalate in mineral soil, which is of particular interest as a potential long-term Ca reservoir, was a larger portion of total available Ca (exchangeable Ca plus Ca oxalate Ca) in the low-Ca site than the high-Ca site (9% versus 1% of available soil Ca, respectively). Calcium oxalate was the dominant form of Ca returned from plants to soil as leaf litterfall at the high-Ca site, yet calcium oxalate disappeared rapidly from decomposing litter (0.28 yr−1 or faster) at both sites. We conclude that accumulation of Ca oxalate in forest ecosystems appears most closely related to overall Ca supply for live biomass pools, and that the accumulation of Ca oxalate in forest floor and mineral soil is limited by rapid microbial degradation of putatively unavailable Ca oxalate.

  14. Differential response of carbon cycling to long-term nutrient input and altered hydrological conditions in a continental Canadian peatland

    Science.gov (United States)

    Berger, Sina; Praetzel, Leandra S. E.; Goebel, Marie; Blodau, Christian; Knorr, Klaus-Holger

    2018-02-01

    Peatlands play an important role in global carbon cycling, but their responses to long-term anthropogenically changed hydrologic conditions and nutrient infiltration are not well known. While experimental manipulation studies, e.g., fertilization or water table manipulations, exist on the plot scale, only few studies have addressed such factors under in situ conditions. Therefore, an ecological gradient from the center to the periphery of a continental Canadian peatland bordering a eutrophic water reservoir, as reflected by increasing nutrient input, enhanced water level fluctuations, and increasing coverage of vascular plants, was used for a case study of carbon cycling along a sequence of four differently altered sites. We monitored carbon dioxide (CO2) and methane (CH4) surface fluxes and dissolved inorganic carbon (DIC) and CH4 concentrations in peat profiles from April 2014 through September 2015. Moreover, we studied bulk peat and pore-water quality and we applied δ13C-CH4 and δ13C-CO2 stable isotope abundance analyses to examine dominant CH4 production and emission pathways during the growing season of 2015. We observed differential responses of carbon cycling at the four sites, presumably driven by abundances of plant functional types and vicinity to the reservoir. A shrub-dominated site in close vicinity to the reservoir was a comparably weak sink for CO2 (in 1.5 years: -1093 ± 794, in 1 year: +135 ± 281 g CO2 m-2; a net release) as compared to two graminoid-moss-dominated sites and a moss-dominated site (in 1.5 years: -1552 to -2260 g CO2 m-2, in 1 year: -896 to -1282 g CO2 m-2). Also, the shrub-dominated site featured notably low DIC pore-water concentrations and comparably 13C-enriched CH4 (δ13C- CH4: -57.81 ± 7.03 ‰) and depleted CO2 (δ13C-CO2: -15.85 ± 3.61 ‰) in a more decomposed peat, suggesting a higher share of CH4 oxidation and differences in predominant methanogenic pathways. In comparison to all other sites, the graminoid

  15. Long Term Effects of Acid Irrigation at the Hoeglwald on Seepage Water Chemistry and Nutrient Cycling

    International Nuclear Information System (INIS)

    Weis, Wendelin; Baier, Roland; Huber, Christian; Goettlein, Axel

    2007-01-01

    In order to test the hypothesis of aluminium toxicity induced by acid deposition, an experimental acid irrigation was carried out in a mature Norway spruce stand in Southern Germany (Hoeglwald). The experiment comprised three plots: no irrigation, irrigation (170 mm a -1 ), and acid irrigation with diluted sulphuric acid (pH of 2.6-2.8). During the seven years of acid irrigation (1984-1990) water containing 0.43 mol c m -2 a -1 of protons and sulphate was added with a mean pH of 3.2 (throughfall + acid irrigation water) compared to 4.9 (throughfall) on both control plots. Most of the additional proton input was consumed in the organic layer and the upper mineral soil. Acid irrigation resulted in a long lasting elevation of sulphate concentrations in the seepage water. Together with sulphate both aluminium and appreciable amounts of base cations were leached from the main rooting zone. The ratio between base cations (Ca + Mg + K) and aluminium was 0.79 during acid irrigation and 0.92 on the control. Neither tree growth and nutrition nor the pool of exchangeable cations were affected significantly. We conclude that at this site protection mechanisms against aluminium toxicity exist and that additional base cation runoff can still be compensated without further reduction of the supply of exchangeable base cations in the upper mineral soil

  16. Environmental impacts of innovative dairy farming systems aiming at improved internal nutrient cycling: A multi-scale assessment.

    Science.gov (United States)

    de Vries, W; Kros, J; Dolman, M A; Vellinga, Th V; de Boer, H C; Gerritsen, A L; Sonneveld, M P W; Bouma, J

    2015-12-01

    Several dairy farms in the Netherlands aim at reducing environmental impacts by improving the internal nutrient cycle (INC) on their farm by optimizing the use of available on-farm resources. This study evaluates the environmental performance of selected INC farms in the Northern Friesian Woodlands in comparison to regular benchmark farms using a Life Cycle Assessment. Regular farms were selected on the basis of comparability in terms of milk production per farm and per hectare, soil type and drainage conditions. In addition, the environmental impacts of INC farming at landscape level were evaluated with the integrated modelling system INITIATOR, using spatially explicit input data on animal numbers, land use, agricultural management, meteorology and soil, assuming that all farms practised the principle of INC farming. Impact categories used at both farm and landscape levels were global warming potential, acidification potential and eutrophication potential. Additional farm level indicators were land occupation and non-renewable energy use, and furthermore all farm level indicators were also expressed per kg fat and protein corrected milk. Results showed that both on-farm and off-farm non-renewable energy use was significantly lower at INC farms as compared with regular farms. Although nearly all other environmental impacts were numerically lower, both on-farm and off-farm, differences were not statistically significant. Nitrogen losses to air and water decreased by on average 5 to 10% when INC farming would be implemented for the whole region. The impact of INC farming on the global warming potential and eutrophication potential was, however, almost negligible (cycle. Copyright © 2015 Elsevier B.V. All rights reserved.

  17. Proof-of-principle of high-fidelity coupled CRUD deposition and cycle depletion simulation

    International Nuclear Information System (INIS)

    Walter, Daniel J.; Kendrick, Brian K.; Petrov, Victor; Manera, Annalisa; Collins, Benjamin; Downar, Thomas

    2015-01-01

    A multiphysics framework for the high-fidelity simulation of CRUD deposition is developed to better understand the coupled physics and their respective feedback mechanisms. This framework includes the primary physics of lattice depletion, computational fluid dynamics, and CRUD chemistry. The three physics are coupled together via the operator-splitting technique, where predictor–corrector and fixed-point iteration schemes are utilized to converge the nonlinear solution. High-fidelity simulations may provide a means to predict and assess potential operating issues, including CRUD induced power shift and CRUD induced localized corrosion, known as CIPS and CILC, respectively. As a proof-of-principle, a coupled 500-day cycle depletion simulation of a pressurized water reactor fuel pin cell was performed using the coupled code suite; a burnup of 31 MWd/kgHM was reached. The simulation recreated the classic striped CRUD pattern often seen on pulled fuel rods containing CRUD. It is concluded that the striping is caused by the flow swirl induced by spacer grid mixing vanes. Two anti-correlated effects contribute to the striping: (1) the flow swirl yields significant azimuthal temperature variations, which impact the locations where CRUD deposits, and (2) the flow swirl is correlated to increased shear stress along the cladding surface and subsequent erosion of the CRUD layer. The CIPS condition of the core is concluded to be primarily controlled by lithium tetraborate precipitation, referred to as boron hideout, which occurs in regions experiencing subcooled nucleate boiling as soluble boron and lithium species reach their solubility limit within the CRUD layer. Subsequently, a localized reduction in power occurs due to the high neutron absorption cross section of boron-10

  18. Different types of nitrogen deposition show variable effects on the soil carbon cycle process of temperate forests.

    Science.gov (United States)

    Du, Yuhan; Guo, Peng; Liu, Jianqiu; Wang, Chunyu; Yang, Ning; Jiao, Zhenxia

    2014-10-01

    Nitrogen (N) deposition significantly affects the soil carbon (C) cycle process of forests. However, the influence of different types of N on it still remained unclear. In this work, ammonium nitrate was selected as an inorganic N (IN) source, while urea and glycine were chosen as organic N (ON) sources. Different ratios of IN to ON (1 : 4, 2 : 3, 3 : 2, 4 : 1, and 5 : 0) were mixed with equal total amounts and then used to fertilize temperate forest soils for 2 years. Results showed that IN deposition inhibited soil C cycle processes, such as soil respiration, soil organic C decomposition, and enzymatic activities, and induced the accumulation of recalcitrant organic C. By contrast, ON deposition promoted these processes. Addition of ON also resulted in accelerated transformation of recalcitrant compounds into labile compounds and increased CO2 efflux. Meanwhile, greater ON deposition may convert C sequestration in forest soils into C source. These results indicated the importance of the IN to ON ratio in controlling the soil C cycle, which can consequently change the ecological effect of N deposition. © 2014 John Wiley & Sons Ltd.

  19. Iron-dependent nitrogen cycling in a ferruginous lake and the nutrient status of Proterozoic oceans

    Science.gov (United States)

    Michiels, Céline C.; Darchambeau, François; Roland, Fleur A. E.; Morana, Cédric; Llirós, Marc; García-Armisen, Tamara; Thamdrup, Bo; Borges, Alberto V.; Canfield, Donald E.; Servais, Pierre; Descy, Jean-Pierre; Crowe, Sean A.

    2017-01-01

    Nitrogen limitation during the Proterozoic has been inferred from the great expanse of ocean anoxia under low-O2 atmospheres, which could have promoted NO3- reduction to N2 and fixed N loss from the ocean. The deep oceans were Fe rich (ferruginous) during much of this time, yet the dynamics of N cycling under such conditions remain entirely conceptual, as analogue environments are rare today. Here we use incubation experiments to show that a modern ferruginous basin, Kabuno Bay in East Africa, supports high rates of NO3- reduction. Although 60% of this NO3- is reduced to N2 through canonical denitrification, a large fraction (40%) is reduced to NH4+, leading to N retention rather than loss. We also find that NO3- reduction is Fe dependent, demonstrating that such reactions occur in natural ferruginous water columns. Numerical modelling of ferruginous upwelling systems, informed by our results from Kabuno Bay, demonstrates that NO3- reduction to NH4+ could have enhanced biological production, fuelling sulfate reduction and the development of mid-water euxinia overlying ferruginous deep oceans. This NO3- reduction to NH4+ could also have partly offset a negative feedback on biological production that accompanies oxygenation of the surface ocean. Our results indicate that N loss in ferruginous upwelling systems may not have kept pace with global N fixation at marine phosphorous concentrations (0.04-0.13 μM) indicated by the rock record. We therefore suggest that global marine biological production under ferruginous ocean conditions in the Proterozoic eon may thus have been P not N limited.

  20. Dynamic changes of nutrient composition throughout the entire life cycle of black soldier fly.

    Directory of Open Access Journals (Sweden)

    Xiu Liu

    Full Text Available Black soldier fly (BSF larvae, Hermetia illucens L., develops on organic wastes, reducing ecological pollution and converting waste biomass into protein and fat rich insect biomass. BSF can replace increasingly expensive protein sources used in poultry, aquaculture and livestock compound diet formulation, such as fish meal and soybean meal, which holds the potential to alleviate future food and feed insecurity. The fate of nutritional spectra in BSF during its life cycle phases is still poorly understood. This study assessed metabolic changes in nutrition composition of BSF from egg to adult. A rapid increase of crude fat content was observed since the development of 4-14 days of larvae with its maximum level reaching 28.4% in dry mass, whereas the crude protein displayed a continuous decreasing trend in the same development phases with minimum level of 38% at larval phase (12 days and peak level of 46.2% at early pupa stage. A sharp drop in crude fat was noticed from early prepupae to late pupae (24.2%, 8.2% respectively. However crude protein shows its maximum value being 57.6% at postmortem adult stage with 21.6% fat level. In addition, fatty acids, amino acids, minerals and vitamins composition in different development stages of BSF were presented and compared. Findings from this study could provide podium to food and feed industry for framing a strategy for specific molecular nutritional component intake into the diets of humans, aquaculture and animals. It is also indicated that BSF is a possible insect which can be applied to combating the food scarcity of countries where micronutrient deficiency is prevalent. Moreover it contributes to advance exploring for developmental and metabolic biology of this edible insect.

  1. Deposition

    International Nuclear Information System (INIS)

    1984-01-01

    Monitoring of radionuclide contents in rainwater is a useful way to keep a check on any change in the external radiation dose caused by the deposited material. Thus analuses of 3 H, 89 Sr and 90 Sr as well as 137 Cs and other gamma radionuclide contents in deposition were continued both nationwide and in the vicinities of the nuclear power stations at Loviisa and Olkiluoto. The deposition of 90 Sr and 137 Cs was lower than in previous years, being only a small fraction of the highest deposition values measured in 1983. The tritium concentrations were also lower than in 1982. The total annual deposition of tritium at different sampling stations varied from 1.7 kBq/m 2 to 2.9 kBq/m 2

  2. Bacterial active community cycling in response to solar radiation and their influence on nutrient changes in a high altitude wetland

    Directory of Open Access Journals (Sweden)

    Veronica Molina

    2016-11-01

    Full Text Available Microbial communities inhabiting high altitude spring ecosystems are subjected to extreme changes in irradiation and temperature throughout the diel cycle. Here, using 16S rRNA gene tag pyrosequencing (cDNA we determined the composition of actively transcribing bacteria from spring waters experimentally exposed through the day (morning, noon and afternoon to variable levels of solar radiation and light quality, and evaluated their influence on nutrient recycling. Irradiation, temperature and changes in nutrient dynamics were associated with changes in the active bacterial community structure, predominantly by Cyanobacteria, Verrucomicrobia, Proteobacteria, and 35 other Phyla, including the recently described Candidate Phyla Radiation (e.g., Parcubacteria, Gracilibacteria, OP3, TM6, SR1. Diversity increased at noon, when the highest irradiances were measured (3.3 -3.9 H’, 1125 W m-2 compared to morning and afternoon (0.6-2.8 H’. This shift was associated with a decrease in the contribution to pyrolibraries by Cyanobacteria and an increase of Proteobacteria and other initially low frequently and rare bacteria phyla (<0.5% in the pyrolibraries. A potential increase in the activity of Cyanobacteria and other phototrophic groups, e.g., Rhodobacterales, was observed and associated with UVR, suggesting the presence of photo-activated repair mechanisms to resist high levels of solar radiation. In addition, the percentage contribution of cyanobacterial sequences in the afternoon was similar to those recorded in the morning. The shifts in the contribution by Cyanobacteria also influenced the rate of change in nitrate, nitrite and phosphate, highlighted by a high level of nitrate accumulation during hours of high radiation and temperature associated with nitrifying bacteria activity. We did not detect ammonia or nitrite oxidizing bacteria in-situ, but both functional groups (Nitrosomona and Nitrospira appeared mainly in pyrolibraries generated from

  3. Use of cycle stacking patterns to define third-order depositional sequences: Middle to Late Cambrian Bonanza King Formation, southern Great basin

    Energy Technology Data Exchange (ETDEWEB)

    Montanez, I.P.; Droser, M.L. (Univ. of California, Riverside (United States))

    1991-03-01

    The Middle to Late Cambrian Bonanza King Formation (CA, NV) is characterized by superimposed scales of cyclicity. Small-scale cycles (0.5 to 10m) occur as shallowing-upward peritidal and subtidal cycles that repeat at high frequencies (10{sup 4} to 10{sup 5}). Systematic changes in stacking patterns of meter-scale cycles define several large-scale (50-250 m) third-order depositional sequences in the Bonanza King Formation. Third-order depositional sequences can be traced within ranges and correlated regionally across the platform. Peritidal cycles in the Bonanza King Formation are both subtidal- and tidal flat-dominated. Tidal flat-dominated cycles consist of muddy bases grading upward into thrombolites or columnar stromatolites all capped by planar stromatolites. Subtidal cycles in the Bonanza King Formation consist of grainstone bases that commonly fine upward and contain stacked hardgrounds. These are overlain by digitate-algal bioherms with grainstone channel fills and/or bioturbated ribbon carbonates with grainstone lenses. Transgressive depositional facies of third-order depositional sequences consist primarily of stacks of subtidal-dominated pertidial cycles and subtidal cycles, whereas regressive depositional facies are dominated by stacks of tidal flat-dominated peritidal cycles and regoliths developed over laminite cycle caps. The use of high frequency cycles in the Bonanza King Formation to delineate regionally developed third-order depositional sequences thus provides a link between cycle stratigraphy and sequence stratigraphy.

  4. Predicting interwell heterogeneity in fluvial-deltaic reservoirs: Outcrop observations and applications of progressive facies variation through a depositional cycle

    Energy Technology Data Exchange (ETDEWEB)

    Knox, P.R.; Barton, M.D. [Univ. of Texas, Austin, TX (United States)

    1997-08-01

    Nearly 11 billion barrels of mobile oil remain in known domestic fluvial-deltaic reservoirs despite their mature status. A large percentage of this strategic resource is in danger of permanent loss through premature abandonment. Detailed reservoir characterization studies that integrate advanced technologies in geology, geophysics, and engineering are needed to identify remaining resources that can be targeted by near-term recovery methods, resulting in increased production and the postponement of abandonment. The first and most critical step of advanced characterization studies is the identification of reservoir architecture. However, existing subsurface information, primarily well logs, provides insufficient lateral resolution to identify low-permeability boundaries that exist between wells and compartmentalize the reservoir. Methods to predict lateral variability in fluvial-deltaic reservoirs have been developed on the basis of outcrop studies and incorporate identification of depositional setting and position within a depositional cycle. The position of a reservoir within the framework of a depositional cycle is critical. Outcrop studies of the Cretaceous Ferron Sandstone of Utah have demonstrated that the architecture and internal heterogeneity of sandstones deposited within a given depositional setting (for example, delta front) vary greatly depending upon whether they were deposited in the early, progradational part of a cycle or the late, retrogradational part of a cycle. The application of techniques similar to those used by this study in other fluvial-deltaic reservoirs will help to estimate the amount and style of remaining potential in mature reservoirs through a quicklook evaluation, allowing operators to focus characterization efforts on reservoirs that have the greatest potential to yield additional resources.

  5. Exploring the effects of black mangrove (Avicennia germinans) expansions on nutrient cycling in smooth cordgrass (Spartina alterniflora) marsh sediments of southern Louisiana, USA

    Science.gov (United States)

    Henry, K. M.; Twilley, R. R.

    2011-12-01

    Located at the northernmost extent of mangroves in the Gulf of Mexico, coastal Louisiana (LA) provides an excellent opportunity to study the effects of a climate-induced vegetation shift on nutrient cycling within an ecosystem. Climate throughout the Gulf Coast region is experiencing a general warming trend and scientists predict both hotter summers (+1.5 to 4 °C) and warmer winters (+1.5 to 5.5 °C) by 2100. Over the last two decades, mild winter temperatures have facilitated the expansion of black mangrove trees (Avicennia germinans) into the smooth cordgrass (Spartina alterniflora) along parts of the LA coast. Due to differences in morphology and physiology between these two species, the expansion of Avicennia has the potential to greatly alter sediment biogeochemistry, especially nutrient cycling. With such an extensive history of coastal nutrient enrichment and eutrophication in the Mississippi River delta, it is important to understand how nutrient cycling, retention, and removal in this region will be affected by this climate-induced vegetation expansion. We examined the effect of this species shift on porewater salinity, sulfide, and dissolved inorganic nutrient concentrations (nitrite, nitrate, ammonium, and phosphate) as well as sediment oxidation-reduction potential, bulk density, and nutrient content (carbon, nitrogen, phosphorus). We also measured net dinitrogen (N2:Ar), oxygen, and dissolved inorganic nutrient fluxes on intact, non-vegetated sediment cores collected from both Spartina and Avicennia habitats. Spartina sediments were more reducing, with higher concentrations of sulfides and ammonium. We found no significant difference between Spartina and Avicennia sediment dinitrogen, oxygen, or dissolved inorganic nutrient fluxes. Net dinitrogen fluxes for both habitat types were predominately positive, indicating higher rates of denitrification than nitrogen fixation at these sites. Sediments were primarily a nitrate sink, but functioned as both a

  6. Deposition Time and Thermal Cycles of Fabricating Thin-wall Steel Parts by Double Electrode GMAW Based Additive Manufacturing

    Directory of Open Access Journals (Sweden)

    Yang Dongqing

    2017-01-01

    Full Text Available The deposition time for fabricating the thin-wall part as well as the peak temperature of the substrate during the process was analyzed in the double electrode gas metal arc welding (DE-GMAW based additive manufacturing (AM. The total deposition time and the interlayer idle time of the manufacturing process decreased with the increasing of the bypass current under the same interlayer temperature and the same deposition rate. The thermal cycling curves illustrated that the peak temperature of the substrate was lower in the DE-GMAW base AM under the same conditions. When depositing the thin-wall parts, the DE-GMAW based AM can reduce the heat input to the substrate and improve the fabrication efficiency, compared with the GMAW based AM.

  7. Real-time monitoring of asphaltene deposition for solvent job cycle optimization

    NARCIS (Netherlands)

    Boer, J.P. de; Linden, R.J.P. van der; Renes, W.A.

    2015-01-01

    Asphaltene agglomeration and deposition is a complex process, leading to progressive production losses without mitigative actions. Injection of asphaltenes inhibitors (solvents) in the tubing is a common practice to avoid deposition in production tubing. This does however not avoid deposition in the

  8. Ciclagem de nutrientes por plantas de cobertura na entressafra em um solo de cerrado Nutrient cycling in off-season cover crops on a Brazilian savanna soil

    Directory of Open Access Journals (Sweden)

    Carlo Adriano Boer

    2007-09-01

    Full Text Available O objetivo deste trabalho foi avaliar o acúmulo e a liberação de nutrientes (N, P, K, Ca, Mg e S de resíduos culturais de plantas de cobertura na entressafra, em condições de Cerrado. O experimento foi conduzido em um Latossolo Vermelho distroférrico com textura argilosa. As plantas de cobertura avaliadas foram: amaranto (Amaranthus cruentus L., milheto (Pennisetum glaucum L. e capim-pé-de-galinha (Eleusine coracana (L. Gaertn.. O delineamento experimental utilizado foi o de blocos ao acaso, no esquema de parcelas subdivididas, com quatro repetições. Na fase de florescimento das espécies, foi avaliada a produção de matéria seca e o acúmulo de nutrientes. A fim de avaliar a liberação de nutrientes dos resíduos culturais, o material vegetal de cada espécie foi acondicionado em sacolas de náilon, as quais foram dispostas sobre o solo e seu conteúdo analisado em intervalos de 30 dias, até 240 dias após sua instalação. As maiores quantidades de nutrientes acumulados na fitomassa das plantas de cobertura foram observadas no milheto e no capim-pé-de-galinha. O potássio foi o nutriente acumulado em maior quantidade, chegando a atingir 416,9 kg ha-1 no milheto. As maiores taxas de liberação de nutrientes foram observadas nos resíduos culturais do amaranto.The objective of this work was to evaluate the accumulation and the liberation of nutrients (N, P, K, Ca, Mg and S of cultural residues by three species of cover crops, in off-season. Tested cover crops were amaranthus (Amaranthus cruentus L., pearl millet (Pennisetum glaucum L. and finger millet (Eleusine coracana (L. Gaertn.. The experiment was carried out in a Typic Haplorthox clay texture soil. A randomized block desing in a split-plot array in time, with four replications, was used. At the flowering of the species, the production of dry matter and the accumulation of nutrients were evaluated. Proportional samples of dry matter of each cover crop species were placed in

  9. Differences in ecosystem carbon distribution and nutrient cycling linked to forest tree species composition in a mid-successional boreal forest

    Science.gov (United States)

    Melvin, April M.; Mack, Michelle C.; Johnstone, Jill F.; McGuire, A. David; Genet, Helene; Schuur, Edward A.G.

    2015-01-01

    In the boreal forest of Alaska, increased fire severity associated with climate change is expanding deciduous forest cover in areas previously dominated by black spruce (Picea mariana). Needle-leaf conifer and broad-leaf deciduous species are commonly associated with differences in tree growth, carbon (C) and nutrient cycling, and C accumulation in soils. Although this suggests that changes in tree species composition in Alaska could impact C and nutrient pools and fluxes, few studies have measured these linkages. We quantified C, nitrogen, phosphorus, and base cation pools and fluxes in three stands of black spruce and Alaska paper birch (Betula neoalaskana) that established following a single fire event in 1958. Paper birch consistently displayed characteristics of more rapid C and nutrient cycling, including greater aboveground net primary productivity, higher live foliage and litter nutrient concentrations, and larger ammonium and nitrate pools in the soil organic layer (SOL). Ecosystem C stocks (aboveground + SOL + 0–10 cm mineral soil) were similar for the two species; however, in black spruce, 78% of measured C was found in soil pools, primarily in the SOL, whereas aboveground biomass dominated ecosystem C pools in birch forest. Radiocarbon analysis indicated that approximately one-quarter of the black spruce SOL C accumulated prior to the 1958 fire, whereas no pre-fire C was observed in birch soils. Our findings suggest that tree species exert a strong influence over C and nutrient cycling in boreal forest and forest compositional shifts may have long-term implications for ecosystem C and nutrient dynamics.

  10. Influence of atmospheric dry deposition of inorganic nutrients on phytoplankton biomass in the coastal Bay of Bengal

    Digital Repository Service at National Institute of Oceanography (India)

    Yadav, K.; Sarma, V.V.S.S.; Rao, D.B.; DileepKumar, M.

    The aerosols from continents contain relatively higher amounts of inorganic nutrients than those of marine origin and can make a notable contribution to the coastal biological productivity. To test this hypothesis, the composition of aerosols over...

  11. Watershed-scale changes in terrestrial nitrogen cycling during a period of decreased atmospheric nitrate and sulfur deposition

    Science.gov (United States)

    Sabo, Robert D.; Scanga, Sara E.; Lawrence, Gregory B.; Nelson, David M.; Eshleman, Keith N.; Zabala, Gabriel A.; Alinea, Alexandria A.; Schirmer, Charles D.

    2016-01-01

    Recent reports suggest that decreases in atmospheric nitrogen (N) deposition throughout Europe and North America may have resulted in declining nitrate export in surface waters in recent decades, yet it is unknown if and how terrestrial N cycling was affected. During a period of decreased atmospheric N deposition, we assessed changes in forest N cycling by evaluating trends in tree-ring δ15N values (between 1980 and 2010; n = 20 trees per watershed), stream nitrate yields (between 2000 and 2011), and retention of atmospherically-deposited N (between 2000 and 2011) in the North and South Tributaries (North and South, respectively) of Buck Creek in the Adirondack Mountains, USA. We hypothesized that tree-ring δ15N values would decline following decreases in atmospheric N deposition (after approximately 1995), and that trends in stream nitrate export and retention of atmospherically deposited N would mirror changes in tree-ring δ15N values. Three of the six sampled tree species and the majority of individual trees showed declining linear trends in δ15N for the period 1980–2010; only two individual trees showed increasing trends in δ15N values. From 1980 to 2010, trees in the watersheds of both tributaries displayed long-term declines in tree-ring δ15N values at the watershed scale (R = −0.35 and p = 0.001 in the North and R = −0.37 and p <0.001 in the South). The decreasing δ15N trend in the North was associated with declining stream nitrate concentrations (−0.009 mg N L−1 yr−1, p = 0.02), but no change in the retention of atmospherically deposited N was observed. In contrast, nitrate yields in the South did not exhibit a trend, and the watershed became less retentive of atmospherically deposited N (−7.3% yr−1, p < 0.001). Our δ15N results indicate a change in terrestrial N availability in both watersheds prior to decreases in atmospheric N deposition, suggesting that decreased atmospheric N deposition was not the sole driver of

  12. Sediment deposition and occurrence of selected nutrients, other chemical constituents, and diatoms in bottom sediment, Perry Lake, northeast Kansas, 1969-2001

    Science.gov (United States)

    Juracek, Kyle E.

    2003-01-01

    A combination of bathymetric surveying and bottom-sediment coring was used to investigate sediment deposition and the occurrence of selected nutrients (total nitrogen and total phosphorus), organic and total carbon, 26 metals and trace elements, 15 organochlorine compounds, 1 radionuclide, and diatoms in bottom sediment of Perry Lake, northeast Kansas. The total estimated volume and mass of bottom sediment deposited from 1969 through 2001 in the original conservation-pool area of the lake was 2,470 million cubic feet (56,700 acre-feet) and 97,200 million pounds (44,100 million kilograms), respectively. The estimated sediment volume occupied about 23 percent of the original conservation-pool, water-storage capacity of the lake. Mean annual net sediment deposition since 1969 was estimated to be 3,040 million pounds (1,379 million kilograms). Mean annual sediment yield from the Perry Lake Basin was estimated to be 2,740,000 pounds per square mile (4,798 kilograms per hectare). The estimated mean annual net loads of total nitrogen and total phosphorus deposited in the bottom sediment of Perry Lake were 7,610,000 pounds per year (3,450,000 kilograms per year) and 3,350,000 pounds per year (1,520,000 kilograms per year), respectively. The estimated mean annual yields of total nitrogen and total phosphorus from the Perry Lake Basin were 6,850 pounds per square mile per year (12.0 kilograms per hectare per year) and 3,020 pounds per square mile per year (5.29 kilograms per hectare per year), respectively. A statistically significant positive trend for total nitrogen deposition in the bottom sediment of Perry Lake was indicated. However, the trend may be due solely to analytical variance. No statistically significant trend for total phosphorus deposition was indicated. Overall, the transport and deposition of these constituents have been relatively uniform throughout the history of Perry Lake. On the basis of nonenforceable sediment-quality guidelines established by the U

  13. Contemporary deposition and long-term accumulation of sediment and nutrients by tidal freshwater forested wetlands impacted by sea level rise

    Science.gov (United States)

    Noe, Gregory; Hupp, Cliff R.; Bernhardt, Christopher E.; Krauss, Ken W.

    2016-01-01

    Contemporary deposition (artificial marker horizon, 3.5 years) and long-term accumulation rates (210Pb profiles, ~150 years) of sediment and associated carbon (C), nitrogen (N), and phosphorus (P) were measured in wetlands along the tidal Savannah and Waccamaw rivers in the southeastern USA. Four sites along each river spanned an upstream-to-downstream salinification gradient, from upriver tidal freshwater forested wetland (TFFW), through moderately and highly salt-impacted forested wetlands, to oligohaline marsh downriver. Contemporary deposition rates (sediment, C, N, and P) were greatest in oligohaline marsh and lowest in TFFW along both rivers. Greater rates of deposition in oligohaline and salt-stressed forested wetlands were associated with a shift to greater clay and metal content that is likely associated with a change from low availability of watershed-derived sediment to TFFW and to greater availability of a coastal sediment source to oligohaline wetlands. Long-term accumulation rates along the Waccamaw River had the opposite spatial pattern compared to contemporary deposition, with greater rates in TFFW that declined to oligohaline marsh. Long-term sediment and elemental mass accumulation rates also were 3–9× lower than contemporary deposition rates. In comparison to other studies, sediment and associated nutrient accumulation in TFFW are lower than downriver/estuarine freshwater, oligohaline, and salt marshes, suggesting a reduced capacity for surface sedimentation (short-term) as well as shallow soil processes (long-term sedimentation) to offset sea level rise in TFFW. Nonetheless, their potentially large spatial extent suggests that TFFW have a large impact on the transport and fate of sediment and nutrients in tidal rivers and estuaries.

  14. Fused deposition modeling (FDM) fabricated part behavior under tensile stress, thermal cycling, and fluid pressure

    Science.gov (United States)

    Hossain, Mohammad Shojib

    Material extrusion based additive manufacturing (AM) technology, such as fused deposition modeling (FDM), is gaining popularity with the numerous 3D printers available worldwide. FDM technology is advancing from exclusively prototype construction to achieving production-grade quality. Today, FDM-fabricated parts are widely used in the aerospace industries, biomedical applications, and other industries that may require custom fabricated, low volume parts. These applications are and were possible because of the different production grade material options (e.g., acrylonitrile butadiene styrene (ABS), polycarbonate (PC), polyphenylsulfone (PPSF), etc.) available to use in FDM systems. Recent researchers are exploring other material options including polycaprolactone (PCL), polymethylmethacrylate (PMMA), composites containing ceramic, glass and metal fillers, and even metals which depict the diversified materials and possibility of new material options using FDM technology. The understanding of the behavior and mechanical properties of the finished FDM-fabricated parts is of utmost importance in the advancement of this technology. The processing parameters, e.g., build orientation, raster width (RW), contour width (CW), raster angle (RA), and raster to raster air gap (RRAG) are important factors in determining the mechanical properties of FDM fabricated parts. The work presented here focused on the mechanical properties improvement by modifying those build parameters. The main concentration is on how modifying those parameters can improve ultimate tensile stress (UTS), Young's modulus, and tensile strain of the final product. In this research, PC parts were fabricated using three build methods: 1) default method, 2) Insight revision method, and 3) visual feedback method. By modifying build parameters, the highest average UTS obtained for PC was 63.96 MPa which was 7% higher than that of 59.73 MPa obtained using the default build parameters. The parameter modification

  15. Identifying the impacts of land use on water and nutrient cycling in the South-West Mau, Kenya

    Science.gov (United States)

    Jacobs, Suzanne; Weeser, Björn; Breuer, Lutz; Butterbach-Bahl, Klaus; Rufino, Mariana

    2016-04-01

    The Mau Forest is the largest closed canopy forest system and indigenous montane forest in Kenya, covering approximately 400,000 ha. It is the source of twelve major rivers in the Rift Valley and Western Kenya and one of Kenya's five 'water towers' that provide around 10 million people with fresh water. Significant areas have been affected by deforestation and land use changes in the past decades, resulting in a loss of approx. 25% of the forest area. Recent changes in downstream water supply are discussed to be attributed to land use change, though compelling scientific evidence is still lacking. The study area is located in the South-West Mau as a part of the Sondu River basin that drains into Lake Victoria. This area has suffered a forest loss of 25% through conversion of natural forest to smallholder agriculture and tea/tree plantations. A nested catchment approach has been applied, whereby automatic measurement equipment for monitoring discharge, turbidity, nitrate, total and dissolved organic carbon, electrical conductivity and water temperature at a 10 minute interval has been set up at the outlets of three sub-catchments of 27 - 36 km² and the outlet of the 1023 km² major catchment. The dominant land use in the sub-catchments is either natural forest, tea/tree plantation or smallholder agriculture. The river data is complemented by six precipitation gauging stations and three climate stations, that all measure at the same interval. Installed during October 2014, the systems have collected high resolution data for one and a half year now. The high resolution dataset is being analysed for patterns in stream flow and water quality during dry and wet seasons as well as diurnal cycling of nitrate. The results of the different sub-catchments are compared to identify the role of land use in water and nutrient cycling. First results of the high temporal resolution data already indicate that the different types of land use affect the stream nitrate concentration

  16. Effects of sulfate deposition on pore water dissolved organic carbon, nutrients, and microbial enzyme activities in a northern peatland

    Science.gov (United States)

    L.R. Seifert-Monson; B.H. Hill; R.K. Kolka; T.M. Jicha; L.L. Lehto; C.M. Elonen

    2014-01-01

    Export of dissolved organic carbon from lakes and streams has increased throughout Europe and North America over the past several decades. One possible cause is altered deposition chemistry; specifically, decreasing sulfate inputs leading to changes in ionic strength and dissolved organic carbon solubility. To further investigate the relationship between deposition...

  17. Abiotic and biotic controls over biogeochemical cycles in drylands: Insights from climate change and nitrogen deposition experiments on the Colorado Plateau

    Science.gov (United States)

    Reed, S.; Ferrenberg, S.; Tucker, C.; Rutherford, W. A.; Wertin, T. M.; McHugh, T. A.; Morrissey, E.; Kuske, C.; Mueller, R.; Belnap, J.

    2016-12-01

    As for all ecosystems, biogeochemical cycling in drylands represents numerous intricate connections between biotic and abiotic controls. However, patterns of many fundamental ecosystem processes that generally hold across global gradients fall apart at the arid and semiarid end of the spectrum, and data point to an exceptionally strong role for abiotic controls in explaining these patterns. Further, there are multiple dryland characteristics - such as extreme aridity and high UV radiation, as well as specialized biological communities - which can point to a conclusion that "drylands are different". Indeed, drylands are often characterized by their harsh environment, by the diverse classes of biota representing a range of traits aimed at surviving such harsh conditions, and, more recently, by the suggestion of dramatic biotic responses to seemingly subtle changes in abiotic factors. In this talk, we will explore a range of biotic and abiotic controls over fundamental biogeochemical cycling in drylands using data from a suite of manipulation experiments on the Colorado Plateau, USA. We will present results from field treatments that speak to the effects of increasing temperature, altered precipitation regimes, increased nitrogen availability via deposition, and the effects of altered litterfall inputs. Biogeochemical processes we explore will include plant photosynthesis, soil photosynthesis and respiration (with a focus on biological soil crusts), litter decomposition, and nutrient cycling. In addition, we will assess how treatments alter dryland community composition, as well as the resultant feedbacks of community shifts to environmental change. Taken together we will use these diverse datasets to ask questions about what makes drylands different or, instead, if a holistic joining of biotic and abiotic perspectives suggests they are not so different after all. These data will not only lend insight into the partitioning of and balance between biotic and abiotic

  18. Nutrient Cycling and Retention Along a Littoral Gradient in a Dutch Shallow Lake in Relation to Water Level Regime

    NARCIS (Netherlands)

    Sollie, S.; Verhoeven, J.T.A.

    Littoral zones are characterized by gradients in depth and vegetation biomass, influencing nutrient retention capacity. A field experiment was conducted in a Phragmites australis dominated littoral zone to investigate nutrient retention and its effect on surface water quality. Measurements were done

  19. Timing of initiation of macronuclear DNA synthesis is set during the preceding cell cycle in Paramecium tetraurelia: analysis of the effects of abrupt changes in nutrient level

    Energy Technology Data Exchange (ETDEWEB)

    Ching, A.S.L.; Berger, J.D.

    1986-11-01

    In many eukaryotic organisms, initiation of DNA synthesis is associated with a major control point within the cell cycle and reflects the commitment of the cell to the DNA replication-division portion of the cell cycle. In paramecium, the timing of DNA synthesis initiation is established prior to fission during the preceding cell cycle. DNA synthesis normally starts at 0.25 in the cell cycle. When dividing cells are subjected to abrupt nutrient shift-up by transfer from a chemostat culture to medium with excess food, or shift-down from a well-fed culture to exhausted medium, DNA synthesis initiation in the post-shift cell cycle occurs at 0.25 of the parental cell cycle and not at either 0.25 in the post-shift cell cycle or at 0.25 in the equilibrium cell cycle produced under the post-shift conditions. The long delay prior to initiation of DNA synthesis following nutritional shift-up is not a consequence of continued slow growth because the rate of protein synthesis increases rapidly to the normal level after shift-up. Analysis of the relation between increase in cell mass and initiation of DNA synthesis following nutritional shifts indicates that increase in cell mass, per se, is neither a necessary nor a sufficient condition for initiation of DNA synthesis, in spite of the strong association between accumulation of cell mass and initiation of DNA synthesis in cells growing under steady-state conditions.

  20. Timing of initiation of macronuclear DNA synthesis is set during the preceding cell cycle in Paramecium tetraurelia: analysis of the effects of abrupt changes in nutrient level

    International Nuclear Information System (INIS)

    Ching, A.S.L.; Berger, J.D.

    1986-01-01

    In many eukaryotic organisms, initiation of DNA synthesis is associated with a major control point within the cell cycle and reflects the commitment of the cell to the DNA replication-division portion of the cell cycle. In paramecium, the timing of DNA synthesis initiation is established prior to fission during the preceding cell cycle. DNA synthesis normally starts at 0.25 in the cell cycle. When dividing cells are subjected to abrupt nutrient shift-up by transfer from a chemostat culture to medium with excess food, or shift-down from a well-fed culture to exhausted medium, DNA synthesis initiation in the post-shift cell cycle occurs at 0.25 of the parental cell cycle and not at either 0.25 in the post-shift cell cycle or at 0.25 in the equilibrium cell cycle produced under the post-shift conditions. The long delay prior to initiation of DNA synthesis following nutritional shift-up is not a consequence of continued slow growth because the rate of protein synthesis increases rapidly to the normal level after shift-up. Analysis of the relation between increase in cell mass and initiation of DNA synthesis following nutritional shifts indicates that increase in cell mass, per se, is neither a necessary nor a sufficient condition for initiation of DNA synthesis, in spite of the strong association between accumulation of cell mass and initiation of DNA synthesis in cells growing under steady-state conditions

  1. Anthropogenic influences on the input and biogeochemical cycling of nutrients and mercury in Great Salt Lake, Utah, USA

    International Nuclear Information System (INIS)

    Naftz, David; Angeroth, Cory; Kenney, Terry; Waddell, Bruce; Darnall, Nathan; Silva, Steven; Perschon, Clay; Whitehead, John

    2008-01-01

    Despite the ecological and economic importance of Great Salt Lake (GSL), little is known about the input and biogeochemical cycling of nutrients and trace elements in the lake. In response to increasing public concern regarding anthropogenic inputs to the GSL ecosystem, the US Geological Survey (USGS) and US Fish and Wildlife Service (USFWS) initiated coordinated studies to quantify and evaluate the significance of nutrient and Hg inputs into GSL. A 6 per mille decrease in δ 15 N observed in brine shrimp (Artemia franciscana) samples collected from GSL during summer time periods is likely due to the consumption of cyanobacteria produced in freshwater bays entering the lake. Supporting data collected from the outflow of Farmington Bay indicates decreasing trends in δ 15 N in particulate organic matter (POM) during the mid-summer time period, reflective of increasing proportions of cyanobacteria in algae exported to GSL on a seasonal basis. The C:N molar ratio of POM in outflow from Farmington Bay decreases during the summer period, supportive of the increased activity of N fixation indicated by decreasing δ 15 N in brine shrimp and POM. Although N fixation is only taking place in the relatively freshwater inflows to GSL, data indicate that influx of fresh water influences large areas of the lake. Separation of GSL into two distinct hydrologic and geochemical systems from the construction of a railroad causeway in the late 1950s has created a persistent and widespread anoxic layer in the southern part of GSL. This anoxic layer, referred to as the deep brine layer (DBL), has high rates of SO 4 2- reduction, likely increasing the Hg methylation capacity. High concentrations of methyl mercury (CH 3 Hg) (median concentration = 24 ng/L) were observed in the DBL with a significant proportion (31-60%) of total Hg in the CH 3 Hg form. Hydroacoustic and sediment-trap evidence indicate that turbulence introduced by internal waves generated during sustained wind events can

  2. Anthropogenic influences on the input and biogeochemical cycling of nutrients and mercury in Great Salt Lake, Utah, USA

    Energy Technology Data Exchange (ETDEWEB)

    Naftz, David [US Geological Survey, Salt Lake City 84119, UT (United States)], E-mail: dlnaftz@usgs.gov; Angeroth, Cory; Kenney, Terry [US Geological Survey, Salt Lake City 84119, UT (United States); Waddell, Bruce; Darnall, Nathan [US Fish and Wildlife Service, Salt Lake City, UT (United States); Silva, Steven [US Geological Survey, Menlo Park, CA (United States); Perschon, Clay [Utah Division of Wildlife Resources, Salt Lake City, UT (United States); Whitehead, John [Utah Department of Environmental Quality, Salt Lake City, UT (United States)

    2008-06-15

    Despite the ecological and economic importance of Great Salt Lake (GSL), little is known about the input and biogeochemical cycling of nutrients and trace elements in the lake. In response to increasing public concern regarding anthropogenic inputs to the GSL ecosystem, the US Geological Survey (USGS) and US Fish and Wildlife Service (USFWS) initiated coordinated studies to quantify and evaluate the significance of nutrient and Hg inputs into GSL. A 6 per mille decrease in {delta}{sup 15}N observed in brine shrimp (Artemia franciscana) samples collected from GSL during summer time periods is likely due to the consumption of cyanobacteria produced in freshwater bays entering the lake. Supporting data collected from the outflow of Farmington Bay indicates decreasing trends in {delta}{sup 15}N in particulate organic matter (POM) during the mid-summer time period, reflective of increasing proportions of cyanobacteria in algae exported to GSL on a seasonal basis. The C:N molar ratio of POM in outflow from Farmington Bay decreases during the summer period, supportive of the increased activity of N fixation indicated by decreasing {delta}{sup 15}N in brine shrimp and POM. Although N fixation is only taking place in the relatively freshwater inflows to GSL, data indicate that influx of fresh water influences large areas of the lake. Separation of GSL into two distinct hydrologic and geochemical systems from the construction of a railroad causeway in the late 1950s has created a persistent and widespread anoxic layer in the southern part of GSL. This anoxic layer, referred to as the deep brine layer (DBL), has high rates of SO{sub 4}{sup 2-} reduction, likely increasing the Hg methylation capacity. High concentrations of methyl mercury (CH{sub 3}Hg) (median concentration = 24 ng/L) were observed in the DBL with a significant proportion (31-60%) of total Hg in the CH{sub 3}Hg form. Hydroacoustic and sediment-trap evidence indicate that turbulence introduced by internal waves

  3. Nitrogen distribution and cycling through water flows in a subtropical bamboo forest under high level of atmospheric deposition.

    Science.gov (United States)

    Tu, Li-hua; Hu, Ting-xing; Zhang, Jian; Huang, Li-hua; Xiao, Yin-long; Chen, Gang; Hu, Hong-ling; Liu, Li; Zheng, Jiang-kun; Xu, Zhen-Feng; Chen, Liang-hua

    2013-01-01

    The hydrological cycle is an important way of transportation and reallocation of reactive nitrogen (N) in forest ecosystems. However, under a high level of atmospheric N deposition, the N distribution and cycling through water flows in forest ecosystems especially in bamboo ecosystems are not well understood. In order to investigate N fluxes through water flows in a Pleioblastus amarus bamboo forest, event rainfall/snowfall (precipitation, PP), throughfall (TF), stemflow (SF), surface runoff (SR), forest floor leachate (FFL), soil water at the depth of 40 cm (SW1) and 100 cm (SW2) were collected and measured through the whole year of 2009. Nitrogen distribution in different pools in this ecosystem was also measured. Mean N pools in vegetation and soil (0-1 m) were 351.7 and 7752.8 kg ha(-1). Open field nitrogen deposition at the study site was 113.8 kg N ha(-1) yr(-1), which was one of the highest in the world. N-NH4(+), N-NO3(-) and dissolved organic N (DON) accounted for 54%, 22% and 24% of total wet N deposition. Net canopy accumulated of N occurred with N-NO3(-) and DON but not N-NH4(+). The flux of total dissolved N (TDN) to the forest floor was greater than that in open field precipitation by 17.7 kg N ha(-1) yr(-1), due to capture of dry and cloudwater deposition net of canopy uptake. There were significant negative exponential relationships between monthly water flow depths and monthly mean TDN concentrations in PP, TF, SR, FFL and SW1. The open field nitrogen deposition through precipitation is very high over the world, which is the main way of reactive N input in this bamboo ecosystem. The water exchange and N consume mainly occurred in the litter floor layer and topsoil layer, where most of fine roots of bamboo distributed.

  4. Nitrogen distribution and cycling through water flows in a subtropical bamboo forest under high level of atmospheric deposition.

    Directory of Open Access Journals (Sweden)

    Li-hua Tu

    Full Text Available BACKGROUND: The hydrological cycle is an important way of transportation and reallocation of reactive nitrogen (N in forest ecosystems. However, under a high level of atmospheric N deposition, the N distribution and cycling through water flows in forest ecosystems especially in bamboo ecosystems are not well understood. METHODOLOGY/PRINCIPAL FINDINGS: In order to investigate N fluxes through water flows in a Pleioblastus amarus bamboo forest, event rainfall/snowfall (precipitation, PP, throughfall (TF, stemflow (SF, surface runoff (SR, forest floor leachate (FFL, soil water at the depth of 40 cm (SW1 and 100 cm (SW2 were collected and measured through the whole year of 2009. Nitrogen distribution in different pools in this ecosystem was also measured. Mean N pools in vegetation and soil (0-1 m were 351.7 and 7752.8 kg ha(-1. Open field nitrogen deposition at the study site was 113.8 kg N ha(-1 yr(-1, which was one of the highest in the world. N-NH4(+, N-NO3(- and dissolved organic N (DON accounted for 54%, 22% and 24% of total wet N deposition. Net canopy accumulated of N occurred with N-NO3(- and DON but not N-NH4(+. The flux of total dissolved N (TDN to the forest floor was greater than that in open field precipitation by 17.7 kg N ha(-1 yr(-1, due to capture of dry and cloudwater deposition net of canopy uptake. There were significant negative exponential relationships between monthly water flow depths and monthly mean TDN concentrations in PP, TF, SR, FFL and SW1. CONCLUSIONS/SIGNIFICANCE: The open field nitrogen deposition through precipitation is very high over the world, which is the main way of reactive N input in this bamboo ecosystem. The water exchange and N consume mainly occurred in the litter floor layer and topsoil layer, where most of fine roots of bamboo distributed.

  5. Nutrient Removal and Resource Recovery: Effect on Life Cycle Cost and Environmental Impacts of Small Scale Wastewater Treatment

    Science.gov (United States)

    Many communities across the U.S. are required to upgrade wastewater treatment plants (WWTP) to meet increasingly stringent nutrient effluent standards. However, increased capital, energy and chemical requirements of upgrades create potential trade-offs between eutrophication pote...

  6. Impact of atmospheric and physical forcings on biogeochemical cycling of dissolved oxygen and nutrients in the coastal Bay of Bengal

    Digital Repository Service at National Institute of Oceanography (India)

    Sarma, V.V.S.S.; Sridevi, B.; Maneesha, K.; Sridevi, T.; Naidu, S.A; Prasad, V.R.; Venkataramana, V.; Acharya, T.; Bharati, M; Subbaiah, C.V.; Kiran, B.S.; Reddy, N.P.C.; Sarma, V.V.; Sadhuram, Y.; Murty, T.V.R.

    Time-series observations were conducted off Visakhapatnam, central west coast of Bay of Bengal, from October 2007 to April 2009 to examine the influence of physical and atmospheric processes on water column nutrients biogeochemistry. The thermal...

  7. Chemical cycling and deposition of atmospheric mercury in polar regions: review of recent measurements and comparison with models

    Directory of Open Access Journals (Sweden)

    H. Angot

    2016-08-01

    Full Text Available Mercury (Hg is a worldwide contaminant that can cause adverse health effects to wildlife and humans. While atmospheric modeling traces the link from emissions to deposition of Hg onto environmental surfaces, large uncertainties arise from our incomplete understanding of atmospheric processes (oxidation pathways, deposition, and re-emission. Atmospheric Hg reactivity is exacerbated in high latitudes and there is still much to be learned from polar regions in terms of atmospheric processes. This paper provides a synthesis of the atmospheric Hg monitoring data available in recent years (2011–2015 in the Arctic and in Antarctica along with a comparison of these observations with numerical simulations using four cutting-edge global models. The cycle of atmospheric Hg in the Arctic and in Antarctica presents both similarities and differences. Coastal sites in the two regions are both influenced by springtime atmospheric Hg depletion events and by summertime snowpack re-emission and oceanic evasion of Hg. The cycle of atmospheric Hg differs between the two regions primarily because of their different geography. While Arctic sites are significantly influenced by northern hemispheric Hg emissions especially in winter, coastal Antarctic sites are significantly influenced by the reactivity observed on the East Antarctic ice sheet due to katabatic winds. Based on the comparison of multi-model simulations with observations, this paper discusses whether the processes that affect atmospheric Hg seasonality and interannual variability are appropriately represented in the models and identifies research gaps in our understanding of the atmospheric Hg cycling in high latitudes.

  8. The integrated forest study on effects of atmospheric deposition; A status report

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, D.W.; Lindberg, S.E.; Bondietti, E.A. (Oak Ridge National Lab., TN (USA)); Cole, D.W. (Washington Univ., Seattle, WA (USA)); Lovett, G.M. (Cary Aboretum, Millbrook, NY (US)); Mitchell, M. (State Univ. of New York, Syracuse, NY (USA)); Ragsdale, L.H. (Emory Univ., Atlanta, GA (USA))

    1987-01-01

    The principal objective of the Integrated Forest Study on Effects of Atmospheric Deposition is to determine the effects of atmospheric deposition at sulfur and nitrogen on forest nutrient cycling. The study integrates a field monitoring component, involving quantification of atmospheric deposition and nutrient cycling in a variety of forest sites, and experimental research, including laboratory and field studies to investigate selected atmospheric and soil processes in great detail. The research is being conducted at forested sites in the northwestern, northeastern, and southeastern United States and in Norway. The sites selected for this study represent a range of conditions in climate, air quality, soils, and vegetation, which will facilitate testing hypotheses about the effects of atmospheric sulfur and nitrogen deposition on forest nutrient cycles. Preliminary results show a wide range in atmospheric sulfur and nitrogen deposition and in ecosystem responses to such deposition, some of which are consistent with previous predictions.

  9. Impacts of nitrogen deposition on ecosystem services in interaction with other nutrients, air pollutants and climate change

    NARCIS (Netherlands)

    Vries, de W.; Goodale, C.; Erisman, J.W.; Hettelingh, J.P.

    2014-01-01

    Nitrogen (N) deposition affects many ecosystem services, ranging from: (i) provisioning services such as timber/wood fuel production, (ii) regulating services such as carbon sequestration and pollutant filtering leading to the provision of clean air and water, (iii) supporting services such as

  10. Increased Intake of Foods with High Nutrient Density Can Help to Break the Intergenerational Cycle of Malnutrition and Obesity

    Directory of Open Access Journals (Sweden)

    Barbara Troesch

    2015-07-01

    Full Text Available A workshop held at the University Medical Center in Groningen, The Netherlands, aimed at discussing the nutritional situation of the population in general and the role diet plays during critical windows in the life course, during which the body is programmed for the development of non-communicable diseases (NCDs. NCDs are increasingly prevalent as our society ages, and nutrition is well known to play an important role in determining the risk and the time of onset of many common NCDs. Even in affluent countries, people have difficulties to achieve adequate intakes for a range of nutrients: Economic constraints as well as modern lifestyles lead people to consume diets with a positive energy balance, but low in micronutrients, resulting in increasing prevalence of obesity and suboptimal nutritional status. Information about nutrient density, which refers to the content of micronutrients relative to energy in food or diets, can help identify foods that have a low calorie to nutrient ratio. It thus allows the consumption of diets that cover nutritional needs without increasing the risk of becoming obese. Given the impact a nutrient dense, low energy diet can have on health, researchers, food industry and governments jointly should develop options for affordable, appealing nutrient-rich food products, which, in combination with physical activity, allow for optimal health throughout the life-course.

  11. Influence of the stage of the hair cycle on Cd deposition in hair

    International Nuclear Information System (INIS)

    Kollmer, W.E.

    1980-01-01

    Shortly after a single injection of Cd a much higher deposition of Cd was observed in growing hair (anaphase) than in resting hair (telophase). Shifting the time of the administration in a period ranging from 7 d before the onset of matrix production to full hair growth did not appreciably alter the initial deposition in spite of the rapid decline of Cd in blood plasma. After the initial deposition the concentration decreased in growing as well as in resting hair. In growing hair this is attributed to the addition of new matrix containing less Cd due to its declining supply via blood. In the resting hair it may reflect the decline of Cd in the follicular tissue adhering to the hair roots. The study demonstrates that the deposition of internal Cd in hair occurs mainly in those sections of hair growing at the time of the actual intake of Cd into the organism. The quantity of Cd found in a particular section of hair in the absence of external contamination, indicates first and foremost the quantity of Cd taken up into the blood stream - after ingestion or inhalation -at the time of the actual formation of this section notwithstanding the actual body burden at that time. (author)

  12. Reconstructing the Mineralogy and Bioavailability of Dust-Borne Iron Deposited to the Southern Ocean through the Last Glacial Cycle

    Science.gov (United States)

    Shoenfelt, E. M.; Winckler, G.; Lamy, F.; Bostick, B. C.

    2017-12-01

    The iron (Fe) in dust deposited to the Fe-limited Southern Ocean plays an important role in ocean biogeochemistry and global climate. For instance, increases in dust-borne Fe deposition in the subantarctic Southern Ocean have been linked to increases in productivity and part of the CO2 drawdown of the last glacial cycle [1]. Notably, bioavailable Fe impacts productivity rather than total Fe. While it has long been understood that Fe mineralogy impacts Fe bioavailability in general, our understanding of the mineralogy of Fe in dust in specific is limited to that in modern dust sources. Reduced mineral Fe in dust has been shown to be more bioavailable than oxidized mineral iron, as it is more readily dissolved [2], and it is more easily utilized directly by a model diatom [3]. Our previous work focusing on South American dust sources shows that glacial activity is associated with higher Fe(II) fractions in dust-borne minerals, due to the physical weathering of Fe(II)-rich silicates in bedrock [3]. Thus, we hypothesize that there were higher Fe(II) fractions in dust deposited during cold glacial periods where ice sheets were more widespread. Using synchrotron-based X-ray absorption spectroscopy, we have reconstructed the mineralogy of Fe deposited to Southern Ocean sediment cores from the subantarctic South Atlantic (TN057-6/ODP Site 1090) and South Pacific (PS7/56-1) through the last glacial cycle, creating the first paleorecord of Fe mineralogy and its associated bioavailability. During cold glacial periods there is a higher fraction of reduced Fe - in the form of Fe(II) silicates - deposited to the sediments compared to warm interglacial periods. Thus, Fe(II) content is directly correlated with dust input. The presence of Fe(II) silicates rather than products of diagenesis such as pyrite suggests that these Fe(II) minerals are physically weathered from bedrock and preserved rather than produced in the sediment. This result suggests that not only was there more dust

  13. Evolution of in situ conductivity of polythiophene deposits by potential cycling

    Energy Technology Data Exchange (ETDEWEB)

    Zotti, G.; Schiavon, G. (Ist. di Polarografia ed Elettrochimica Preparativa, Consiglio Nazionale delle Ricerche, Padua (Italy))

    1990-12-01

    In situ conductivity of polythiophene (PT) deposits from anodic coupling of thiophene (T), bithiophene (BT) and terthiophene (TT) increases with redox switching to an extent which depends on the monomer. Changes are considerable with TT, minor with BT and negligible with T, involving extra oxidative charges with the same trend, and are paralleled by evolution of electronic and infrared spectra and cyclic voltammograms. Results are explained by the occurrence of solid-state polymerization of oligomers leading ultimately to the same polymer with a conductivity of 1-3 S cm{sup -1}. PT from thiophene is much less conducting (0.06 S cm{sup -1}), because of oxidative degradation during deposition. (orig.).

  14. Seasonal greenhouse gas and soil nutrient cycling in semi-arid native and non-native perennial grass pastures

    Science.gov (United States)

    Previous research indicates that a difference occurs in native and non-native grass species in regard to drivers of greenhouse gas (GHG, (carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O))) emissions from soil. Drivers of soil nutrients could help establish best management practices to mit...

  15. Major changes in forest carbon and nitrogen cycling caused by declining sulphur deposition

    Czech Academy of Sciences Publication Activity Database

    Oulehle, F.; Evans, C. D.; Hofmeister, J.; Krejci, R.; Tahovská, K.; Persson, T.; Cudlín, Pavel; Hruška, J.

    2011-01-01

    Roč. 17, č. 10 (2011), 3115–3129 ISSN 1354-1013 R&D Projects: GA MŠk OC10022 Institutional research plan: CEZ:AV0Z60870520 Keywords : acidification * carbon * deposition * DOC * forest floor * leaching * nitrogen * nitrogen saturation * soil * sulphur Subject RIV: DD - Geochemistry Impact factor: 6.862, year: 2011 http://onlinelibrary.wiley.com/doi/10.1111/j.1365-2486.2011.02468.x/pdf

  16. Nitrogen Dynamics in European Forest Ecosystems: Considerations regarding Anthropogenic Nitrogen Depositions

    OpenAIRE

    Agren, G.I.; Kauppi, P.

    1983-01-01

    This study deals with the nutrient cycle of forest ecosystems over large geographic regions in Europe as affected by nitrogen deposition. The view is taken that the nitrogen cycle of a forest ecosystem has a maximum capacity for circulating nitrogen. Two different cases are defined: case (1) in which the nutrient cycle functions below its maximum capacity, and case (2) in which the circulation operates at the maximum level.

  17. Interglacial-glacial cycles recorded in the deposit sequence at Kruzhyky on the Dniester River (East Carpathian Foreland)

    Science.gov (United States)

    Łanczont, Maria; Boguckyj, Aandrij; Mroczek, Przemysław; Zieliński, Paweł; Jacyszyn, Andrij; Pidek, Agnieszka I.; Urban, Danuta; Kulesza, Piotr; Hołub, Beata

    2010-01-01

    horizontal stratification and silts with horizontal or flaser lamination; single small-scale lithofacies of sands with trough cross-stratification occur in places; single gravel grains are numerous. Two deformation horizons are found: the higher one is characterized by the occurrence of folds and flexure deflections, and the lower one-involution structures and casts of ice wedges/fissures. This complex is probably the result of deposition on the distal part of flat, periodically inundated fluvioglacial fan connected with advancing ice sheet. 4. Ablation complex-sandy or sandy-silty diamicton occurring as isolated inserts, lenses or tongues. Its lower boundary is sharp, erosional and uneven (concave). This complex represents flows of supraglacial tills, which strongly deformed the deposits of the underlying complex 3. 5. Aeolian complex-silty (loess) and sandy-silty (Table 1) deposits with distinct traces of intensive, postsedimentary alterations of pedogenesis of different ages (Tables 1 and 2). It is composed of two soil units separated by thin, primary loess layer: a) older, well-developed paleosol with several pedofeatures very typical of the Sokal (Mazovian) soil; b) younger unit developed as pedocomplex consisting of two mature soils, the upper of which ("modern" neosol) is formed in the top of relict and exhumed paleosol. The described paleosols should be recognized as at least two soils of different ages and of interglacial rank, developed in periglacial loess-like deposits. The Kruzhyky profile is unique in the Dniester River valley. On account of its situation, it supplements the former information about the terrace 5 structure, which has been determined in detail in the Halyč site. And what is most important, it is the only site on the terrace 5 where glacial deposits were found. Lithofacial analysis carried out in the profile enables us to reconstruct the following events reflecting interglacial-glacial cycles: 1. The lowest, gravelly-sandy unit indicates the

  18. Biomass and nutrient cycling in pure and mixed stands of native tree species in southeastern Bahia, Brazil Biomassa e ciclagem de nutrientes por espécies florestais nativas em plantio puro e misto no sudeste da Bahia, Brasil

    Directory of Open Access Journals (Sweden)

    Antonio Carlos da Gama-Rodrigues

    2007-04-01

    Full Text Available The objective of this paper is to study selected components of the nutrient cycle of pure and mixed stands of native forest species of Atlantic Forest in southeastern Brazil. Tree diameter, height, above-ground biomass, and nutrient content were determined in 22-year-old stands. Litterfall, litter decomposition, and nutrient concentration were evaluated from August 1994 to July 1995. The following species were studied: Peltogyne angustiflora, Centrolobium robustum, Arapatiella psilophylla, Sclerolobium chrysophyllum, Cordia trichotoma, Macrolobium latifolium. The litter of a natural forest and a 40-year-old naturally regenerated second-growth forest was sampled as well. The mixed-species outmatched pure stands in height, stem volume and total biomass (29.4 % more. The greatest amount of forest litter was observed in the natural forest (9.3 Mg ha-1, followed by the mixed-species stand (7.6 Mg ha-1 and secondary forest (7.3 Mg ha-1, and least litterfall was measured in the pure C. robustum stand (5.5 Mg ha-1. Litterfall seasonality varied among species in pure stands (CV from 44.7 to 91.4 %, unlike litterfall in the mixed-tree stand, where the variation was lower (CV 31.2 %. In the natural and second-growth forest, litterfall varied by 57.8 and 34.0 %, respectively. The annual rate of nutrient return via litterfall varied widely among forest ecosystems. Differences were detected between forest ecosystems in both the litter accumulation and quantity of litterlayer nutrients. The highest mean nutrient accumulation in above-ground biomass was observed in mixed-species stands. The total nutrient accumulation (N + P + K+ Ca + Mg ranged from 0.97 to 1.93 kg tree-1 in pure stands, and from 1.21 to 2.63 kg tree-1 in mixed-species stands. Soil fertility under mixed-species stands (0-10 cm was intermediate between the primary forest and pure-stand systems. The litterfall rate of native forest species in a mixed-species system is more constant, resulting in

  19. Dynamic changes in charge-transfer resistance at Li metal/Li7La3Zr2O12 interfaces during electrochemical Li dissolution/deposition cycles

    Science.gov (United States)

    Koshikawa, Hiroyuki; Matsuda, Shoichi; Kamiya, Kazuhide; Miyayama, Masaru; Kubo, Yoshimi; Uosaki, Kohei; Hashimoto, Kazuhito; Nakanishi, Shuji

    2018-02-01

    Dynamic changes in the charge-transfer resistance at a Li/Li7La3Zr2O12 (LLZ) interface during lithium (Li) dissolution/deposition cycles are investigated with an alternative current (AC) impedance technique in a three-electrode system. The resistance respectively increases and decreases during electrodissolution and electrodeposition of Li. The resistance does not return to the initial value after one cycle of Li dissolution and deposition, which indicates that the change in resistance during dissolution is larger than that during deposition. Furthermore, the resistance is almost constant when Li deposition proceeds without prior Li dissolution. The respective increase and decrease in the interfacial resistance during Li dissolution and deposition is most likely due to the formation and disappearance of voids at the Li/LLZ interface, and the voids formation during Li dissolution is suggested to be a critical factor that influences the interfacial resistance.

  20. Approaches and uncertainties in nutrient budgets; Implications for nutrient management and environmental policies

    NARCIS (Netherlands)

    Oenema, O.; Kros, J.; Vries, de W.

    2003-01-01

    Nutrient budgets of agroecosystems are constructed either (i) to increase the understanding of nutrient cycling, (ii) as performance indicator and awareness raiser in nutrient management and environmental policy, or (iii) as regulating policy instrument to enforce a certain nutrient management

  1. Anthropogenic nitrogen deposition in boreal forests has a minor impact on the global carbon cycle.

    Science.gov (United States)

    Gundale, Michael J; From, Fredrik; Bach, Lisbet H; Nordin, Annika

    2014-01-01

    It is proposed that increases in anthropogenic reactive nitrogen (Nr ) deposition may cause temperate and boreal forests to sequester a globally significant quantity of carbon (C); however, long-term data from boreal forests describing how C sequestration responds to realistic levels of chronic Nr deposition are scarce. Using a long-term (14-year) stand-scale (0.1 ha) N addition experiment (three levels: 0, 12.5, and 50 kg N ha(-1)  yr(-1) ) in the boreal zone of northern Sweden, we evaluated how chronic N additions altered N uptake and biomass of understory communities, and whether changes in understory communities explained N uptake and C sequestration by trees. We hypothesized that understory communities (i.e. mosses and shrubs) serve as important sinks for low-level N additions, with the strength of these sinks weakening as chronic N addition rates increase, due to shifts in species composition. We further hypothesized that trees would exhibit nonlinear increases in N acquisition, and subsequent C sequestration as N addition rates increased, due to a weakening understory N sink. Our data showed that understory biomass was reduced by 50% in response to the high N addition treatment, mainly due to reduced moss biomass. A (15) N labeling experiment showed that feather mosses acquired the largest fraction of applied label, with this fraction decreasing as the chronic N addition level increased. Contrary to our hypothesis, the proportion of label taken up by trees was equal (ca. 8%) across all three N addition treatments. The relationship between N addition and C sequestration in all vegetation pools combined was linear, and had a slope of 16 kg C kg(-1)  N. While canopy retention of Nr deposition may cause C sequestration rates to be slightly different than this estimate, our data suggest that a minor quantity of annual anthropogenic CO2 emissions are sequestered into boreal forests as a result of Nr deposition. © 2013 John Wiley & Sons Ltd.

  2. Sulfur Cycling in an Iron Oxide-Dominated, Dynamic Marine Depositional System: The Argentine Continental Margin

    Directory of Open Access Journals (Sweden)

    Natascha Riedinger

    2017-05-01

    Full Text Available The interplay between sediment deposition patterns, organic matter type and the quantity and quality of reactive mineral phases determines the accumulation, speciation, and isotope composition of pore water and solid phase sulfur constituents in marine sediments. Here, we present the sulfur geochemistry of siliciclastic sediments from two sites along the Argentine continental slope—a system characterized by dynamic deposition and reworking, which result in non-steady state conditions. The two investigated sites have different depositional histories but have in common that reactive iron phases are abundant and that organic matter is refractory—conditions that result in low organoclastic sulfate reduction rates (SRR. Deposition of reworked, isotopically light pyrite and sulfurized organic matter appear to be important contributors to the sulfur inventory, with only minor addition of pyrite from organoclastic sulfate reduction above the sulfate-methane transition (SMT. Pore-water sulfide is limited to a narrow zone at the SMT. The core of that zone is dominated by pyrite accumulation. Iron monosulfide and elemental sulfur accumulate above and below this zone. Iron monosulfide precipitation is driven by the reaction of low amounts of hydrogen sulfide with ferrous iron and is in competition with the oxidation of sulfide by iron (oxyhydroxides to form elemental sulfur. The intervals marked by precipitation of intermediate sulfur phases at the margin of the zone with free sulfide are bordered by two distinct peaks in total organic sulfur (TOS. Organic matter sulfurization appears to precede pyrite formation in the iron-dominated margins of the sulfide zone, potentially linked to the presence of polysulfides formed by reaction between dissolved sulfide and elemental sulfur. Thus, SMTs can be hotspots for organic matter sulfurization in sulfide-limited, reactive iron-rich marine sedimentary systems. Furthermore, existence of elemental sulfur and iron

  3. Changes in water mass exchange between the NW shelf areas and the North Atlantic and their impact on nutrient/carbon cycling

    Science.gov (United States)

    Gröger, Matthias; Maier-Reimer, Ernst; Mikolajewicz, Uwe; Segschneider, Joachim; Sein, Dimitry

    2010-05-01

    Despite their comparatively small extension on a global scale, shelf areas are of interest for several economic reasons and climatic processes related to nutrient cycling, sea food supply, and biological productivity. Moreover, they constitute an important interface for nutrients, pollutants and freshwater on their pathway from the continents to the open ocean. This modelling study aims to investigate the spatial and temporal variability of water mass exchange between the North Atlantic and the NW European shelf and their impact on nutrient/carbon cycling and biological productivity. For this, a new modeling approach has been set up which bridges the gap between pure shelf models where water mass transports across the model domain too strongly depend on the formulation of open boundaries and global models suffering under their too coarse resolution in shelf regions. The new model consists of the global ocean and carbon cycle model MPIOM/HAMOCC with strongly increased resolution in the North Sea and the North Atlantic coupled to the regional atmosphere model REMO. The model takes the full luni-solar tides into account. It includes further a 12 layer sediment module with the relevant pore water chemistry. The main focus lies on the governing mechanisms of water mass exchange across the shelf break and the imprint on shelf biogeochemistry. For this, artificial tracers with a prescribed decay rate have been implemented to distinguish waters arriving from polar and shelf regions and those that originate from the tropics. Experiments were carried out for the years 1948 - 2007. The relationship to larger scale circulation patterns like the position and variability of the subtropical and subpolar gyres is analyzed. The water mass exchange is analyzed with respect to the nutrient concentration and productivity on the European shelf areas. The implementation of tides leads to an enhanced vertical mixing which causes lower sea surface temperatures compared to simulations

  4. Martian base agriculture: The effect of low gravity on water flow, nutrient cycles, and microbial biomass dynamics

    Science.gov (United States)

    Maggi, Federico; Pallud, Céline

    2010-11-01

    The latest advances in bioregenerative strategies for long-term life support in extraterrestrial outposts such as on Mars have indicated soil-based cropping as an effective approach for waste decomposition, carbon sequestration, oxygen production, and water biofiltration as compared to hydroponics and aeroponics cropping. However, it is still unknown if cropping using soil systems could be sustainable in a Martian greenhouse under a gravity of 0.38 g. The most challenging aspects are linked to the gravity-induced soil water flow; because water is crucial in driving nutrient and oxygen transport in both liquid and gaseous phases, a gravitational acceleration lower than g = 9.806 m s -2 could lead to suffocation of microorganisms and roots, with concomitant emissions of toxic gases. The effect of Martian gravity on soil processes was investigated using a highly mechanistic model previously tested for terrestrial crops that couples soil hydraulics and nutrient biogeochemistry. Net leaching of NO3- solute, gaseous fluxes of NH 3, CO 2, N 2O, NO and N 2, depth concentrations of O 2, CO 2 and dissolved organic carbon (DOC), and pH in the root zone were calculated for a bioregenerative cropping unit under gravitational acceleration of Earth and for its homologous on Mars, but under 0.38 g. The two cropping units were treated with the same fertilizer type and rate, and with the same irrigation regime, but under different initial soil moisture content. Martian gravity reduced water and solute leaching by about 90% compared to Earth. This higher water holding capacity in soil under Martian gravity led to moisture content and nutrient concentrations that favoured the metabolism of various microbial functional groups, whose density increased by 5-10% on Mars as compared to Earth. Denitrification rates became substantially more important than on Earth and ultimately resulted in 60%, 200% and 1200% higher emissions of NO, N 2O and N 2 gases, respectively. Similarly, O 2 and DOC

  5. Relation between dietary lipid level and voluntary feed intake, growth, nutrient gain, lipid deposition and hepatic lipogenesis in rainbow trout.

    Science.gov (United States)

    Gélineau, A; Corraze, G; Boujard, T; Larroquet, L; Kaushik, S

    2001-01-01

    Four diets with differing lipid contents (15, 20, 25 or 30% DM) were tested on small (initial body weight: 27 g) and larger (IBW: 93 g) rainbow trout (Oncorhynchus mykiss) fed on demand or by hand, respectively. In both trials, voluntary feed intake was inversely related to dietary lipid levels. Protein efficiency increased when dietary fat content increased. Final whole-body lipid content was positively related to dietary lipid levels. The main sites of lipid storage were visceral adipose tissue and to a lesser extent muscle. Increased fat deposition in the visceral cavity of young trout was due to both hyperplasic and hypertrophic responses and in larger trout mostly due to a hypertrophic response. Liver activities of glucose-6-phosphate dehydrogenase and fatty acid synthetase were negatively correlated with fat intake and positively with starch intake, whereas malic enzyme was little affected by dietary treatments.

  6. Isocaloric high-fat feeding directs hepatic metabolism to handling of nutrient imbalance promoting liver fat deposition

    KAUST Repository

    Diaz Rua, Ruben

    2016-03-22

    Background/Objectives: Consumption of fat-rich foods is associated with obesity and related alterations. However, there is a group of individuals, the metabolically obese normal-weight (MONW) subjects, who present normal body weight but have metabolic features characteristic of the obese status, including fat deposition in critical tissues such as liver, recognized as a major cause for the promotion of metabolic diseases. Our aim was to better understand metabolic alterations present in liver of MONW rats applying whole genome transcriptome analysis. Methods: Wistar rats were chronically fed a high-fat diet isocaloric relative to Control animals to avoid the hyperphagia and overweight and to mimic MONW features. Liver transcriptome analysis of both groups was performed. Results: Sustained intake of an isocaloric high-fat diet had a deep impact on the liver transcriptome, mainly affecting lipid metabolism. Although serum cholesterol levels were not affected, circulating triacylglycerols were lower, and metabolic adaptations at gene expression level indicated adaptation toward handling the increased fat content of the diet, an increased triacylglycerol and cholesterol deposition in liver of MONW rats was observed. Moreover, gene expression pointed to increased risk of liver injury. One of the top upregulated genes in this tissue was Krt23, a marker of hepatic disease in humans that was also increased at the protein level.Conclusion:Long-term intake of a high-fat diet, even in the absence of overweight/obesity or increase in classical blood risk biomarkers, promotes a molecular environment leading to hepatic lipid accumulation and increasing the risk of suffering from hepatic diseases.

  7. The impact of pasture conversion on nutrient cycles of tropical streams on the Osa Peninsula, Costa Rica: a paired catchment approach

    Science.gov (United States)

    Bringhurst, K.; Jordan, P.

    2011-12-01

    Changes in nutrient and hydrologic cycles caused by land disturbance typically lead to detrimental changes to ecosystems. This study utilized a paired, small-catchment approach to examine the effect of deforestation on nutrient transfer and hydrological discharge and the resulting impact on soils and streams of the Osa Peninsula, Costa Rica. Two first order streams were chosen, the first catchment had been cleared for pasture and the second consisted of undisturbed tropical wet forest. Soil concentrations of organic matter, total and soil available P were higher in the forested catchment with decreases of >33% of each in the deforested catchment. The effect of deforestation on stream discharge was a 59% increase in flow during the wet season and an increase in the Q5:Q95 ratio showing that the deforested stream was flashier. The deforested catchment loss of dissolved inorganic nitrogen (DIN) increased 95% over the forested catchment. Soluble reactive phosphorus (SRP) showed an increase in load of 43% in the deforested catchment compared to the forested catchment. The molar N:P ratios were lower than the Redfield ratio and both streams were well below the level at which N-limitation of lotic algal growth has been reported, therefore it is hypothesized that N is the limiting nutrient in streams in the study area. Soil nutrient depletion in the deforested catchment, accelerated by a changed hydrologic regime, is the likely trajectory of soil-water interactions in this tropical ecosystem. This will likely be among the secondary impacts should deforestation become widespread along this stretch of the Pacific coastline, with associated eutrophication of receiving transitional and coastal waters.

  8. Life cycle, secondary production and nutrient stock in Heleobia australis (d'Orbigny 1835) (Gastropoda: Hydrobiidae) in a tropical coastal lagoon

    Science.gov (United States)

    Figueiredo-Barros, Marcos P.; Leal, João J. F.; de A. Esteves, Francisco; de M. Rocha, Adriana; Bozelli, Reinaldo L.

    2006-08-01

    The aim of this research was to evaluate density, biomass, life cycle, secondary production and nutrient stock of Heleobia australis population (d'Orbigny 1835) in a coastal tropical lagoon (Imboassica lagoon). Carbon (C), nitrogen (N), phosphorus (P) and organic matter (OM) concentrations in the sediment were determined in order to evaluate their influence on the density, biomass and concentrations of C, N, P and OM in the biomass of H. australis population. Two sampling stations were established: one in the central part of the lagoon (station 1, not influenced directly by sewage release) and the second near the littoral region (station 2, close to the outlet of a canal discharging domestic sewage). Triplicate samples were collected monthly for one year (from May 1999 to April 2000) with a "core" sampler for determination of density, biomass, life cycle and secondary production of H. australis. For determination of C, N, P and OM in both sediment and H. australis, the samples were carried out in May and November 1999, and in April 2000. Density was significantly lower at station 1, whereas biomass did not differ significantly between the stations. Secondary production at station 1 was 28.33 g ash-free dry weight (AFDW) m -2 year -1 and at station 2 it was 49.36 g (AFDW) m -2 year -1. The concentrations of OM, C and P in the sediment and N and P in the biomass of the organisms were higher at station 2. The release of domestic effluents into this lagoon results in an increase in OM, C and P concentrations in the sediment which are reflected in H. australis chemical composition. Considering the high densities, biomass and N and P content of these snails in Imboassica lagoon, their importance for the nutrient cycling in this ecosystem must be accounted.

  9. Investigation of hair dye deposition, hair color loss, and hair damage during multiple oxidative dyeing and shampooing cycles.

    Science.gov (United States)

    Zhang, Guojin; McMullen, Roger L; Kulcsar, Lidia

    2016-01-01

    Color fastness is a major concern for consumers and manufacturers of oxidative hair dye products. Hair dye loss results from multiple wash cycles in which the hair dye is dissolved by water and leaches from the hair shaft. In this study, we carried out a series of measurements to help us better understand the kinetics of the leaching process and pathways associated with its escape from the fiber. Hair dye leaching kinetics was measured by suspending hair in a dissolution apparatus and monitoring the dye concentration in solution (leached dye) with an ultraviolet-visible spectrophotometer. The physical state of dye deposited in hair fibers was evaluated by a reflectance light microscopy technique, based on image stacking, allowing enhanced depth of field imaging. The dye distribution within the fiber was monitored by infrared spectroscopic imaging of hair fiber cross sections. Damage to the ultrafine structure of the hair cuticle (surface, endocuticle, and cell membrane complex) and cortex (cell membrane complex) was determined in hair cross sections and on the hair fiber surface with atomic force microscopy. Using differential scanning calorimetry, we investigated how consecutive coloring and leaching processes affect the internal proteins of hair. Further, to probe the surface properties of hair we utilized contact angle measurements. This study was conducted on both pigmented and nonpigmented hair to gain insight into the influence of melanin on the hair dye deposition and leaching processes. Both types of hair were colored utilizing a commercial oxidative hair dye product based on pyrazole chemistry.

  10. Impact of Aeolian Dry Deposition of Reactive Iron Minerals on Sulfur Cycling in Sediments of the Gulf of Aqaba

    Directory of Open Access Journals (Sweden)

    Barak Blonder

    2017-06-01

    Full Text Available The Gulf of Aqaba is an oligotrophic marine system with oxygen-rich water column and organic carbon-poor sediments (≤0.6% at sites that are not influenced by anthropogenic impact. Aeolian dust deposition from the Arabian, Sinai, and Sahara Deserts is an important source of sediment, especially at the deep-water sites of the Gulf, which are less affected by sediment transport from the Arava Desert during seasonal flash floods. Microbial sulfate reduction in sediments is inferred from the presence of pyrite (although at relatively low concentrations, the presence of sulfide oxidation intermediates, and by the sulfur isotopic composition of sulfate and solid-phase sulfides. Saharan dust is characterized by high amounts of iron minerals such as hematite and goethite. We demonstrated, that the resulting high sedimentary content of reactive iron(III (hydroxides, originating from this aeolian dry deposition of desert dust, leads to fast re-oxidation of hydrogen sulfide produced during microbial sulfate reduction and limits preservation of reduced sulfur in the form of pyrite. We conclude that at these sites the sedimentary sulfur cycle may be defined as cryptic.

  11. High nutrient transport and cycling potential revealed in the microbial metagenome of Australian sea lion (Neophoca cinerea faeces.

    Directory of Open Access Journals (Sweden)

    Trish J Lavery

    Full Text Available Metagenomic analysis was used to examine the taxonomic diversity and metabolic potential of an Australian sea lion (Neophoca cinerea gut microbiome. Bacteria comprised 98% of classifiable sequences and of these matches to Firmicutes (80% were dominant, with Proteobacteria and Actinobacteria representing 8% and 2% of matches respectively. The relative proportion of Firmicutes (80% to Bacteriodetes (2% is similar to that in previous studies of obese humans and obese mice, suggesting the gut microbiome may confer a predisposition towards the excess body fat that is needed for thermoregulation within the cold oceanic habitats foraged by Australian sea lions. Core metabolic functions, including carbohydrate utilisation (14%, protein metabolism (9% and DNA metabolism (7% dominated the metagenome, but in comparison to human and fish gut microbiomes there was a significantly higher proportion of genes involved in phosphorus metabolism (2.4% and iron scavenging mechanisms (1%. When sea lions defecate at sea, the relatively high nutrient metabolism potential of bacteria in their faeces may accelerate the dissolution of nutrients from faecal particles, enhancing their persistence in the euphotic zone where they are available to stimulate marine production.

  12. Direct Measurements of Half-Cycle Reaction Heats during Atomic Layer Deposition by Calorimetry

    Energy Technology Data Exchange (ETDEWEB)

    Lownsbury, James M. [Department; Gladden, James A. [Department; Campbell, Charles T. [Department; Department; Kim, In Soo [Materials; Martinson, Alex B. F. [Materials

    2017-10-05

    We introduce a new high-temperature adsorption calorimeter that approaches the ideal limit of a heat detector whereby the signal at any time is proportional to the heat power being delivered to the sample and prove its sensitivity for measuring pulse-to-pulse heats of half-reactions during atomic layer deposition (ALD) at 400 K. The heat dynamics of amorphous Al2O3 growth via sequential self-limiting surface reaction of trimethylaluminum (TMA) and H2O is clearly resolved. Calibration enables quantitation of the exothermic TMA and H2O half-reactions with high precision, -343 kJ/mol TMA and -251 kJ/mol H2O, respectively. A time resolution better than 1 ms is demonstrated, allowing for the deconvolution of at least two distinct surface reactions during TMA microdosing. It is further demonstrated that this method can provide the heat of reaction versus extent of reaction during each precursors half-reaction, thus providing even richer mechanistic information on the surface processes involved. The broad applicability of this novel calorimeter is demonstrated through excellent signal-to-noise ratios of less exothermic ALD half-reactions to produce TiO2 and MnO.

  13. Sediment deposition and occurrence of selected nutrients and other chemical constituents in bottom sediment, Tuttle Creek Lake, Northeast Kansas, 1962-99

    Science.gov (United States)

    Juracek, K.E.; Mau, D.P.

    2002-01-01

    A combination of bathymetric surveying and bottom-sediment coring was used to investigate sediment deposition and the occurrence of selected nutrients (total ammonia plus organic nitrogen and total phosphorus), 44 metals and trace elements, 15 organochlorine compounds, and 1 radionuclide in bottom sediment of Tuttle Creek Lake, northeast Kansas. The total estimated volume and mass of bottom sediment deposited from 1962 through 1999 in the original conservation-pool area of the lake was 6,170 million cubic feet (142,000 acre-feet) and 292,400 million pounds (133,000 million kilograms), respectively. The volume of sediment occupies about 33 percent of the original conservation-pool, water-storage capacity of the lake. Mean annual net sediment deposition since 1962 was estimated to be 7,900 million pounds (3,600 million kilograms). Mean annual net sediment yield from the Tuttle Creek Lake Basin was estimated to be 821,000 pounds per square mile (1,440 kilograms per hectare). The estimated mean annual net loads of total ammonia plus organic nitrogen and total phosphorus deposited in the bottom sediment of Tuttle Creek Lake were 6,350,000 pounds per year (2,880,000 kilograms per year) and 3,330,000 pounds per year (1,510,000 kilograms per year), respectively. The estimated mean annual net yields of total ammonia plus organic nitrogen and total phosphorus from the Tuttle Creek Lake Basin were 657 pounds per square mile per year (1.15 kilograms per hectare per year) and 348 pounds per square mile per year (0.61 kilograms per hectare per year), respectively. No statistically significant trend for total phosphorus deposition in the bottom sediment of Tuttle Creek Lake was indicated (trend analysis for total ammonia plus organic nitrogen was not performed). On the basis of available sediment-quality guidelines, the concentrations of arsenic, chromium, copper, nickel, silver, and zinc in the bottom sediment of Tuttle Creek Lake frequently or typically exceeded the threshold

  14. The links between global carbon, water and nutrient cycles in an urbanizing world — the case of coastal eutrophication

    NARCIS (Netherlands)

    Kroeze, C.; Hofstra, N.; Ivens, W.; Löhr, A.; Strokal, M.; Wijnen, van J.

    2013-01-01

    The natural cycles of carbon (C), nitrogen (N), phosphorus (P) and water have been disturbed substantially by human activities. Urbanizing coastal drainage basins and large river deltas are located at the interface of freshwater and coastal components of the larger earth system and the process of

  15. Nutrient cycling potential of camelina (Camelina sativa L. Crantz.) as a cover crop in the US Northern Great Plains

    Science.gov (United States)

    Berti, Marisol; Samarappuli, Dulan

    2017-04-01

    Camelina [Camelina sativa (L.) Crantz.] is an industrial oilseed crop in the Brassicaceae family with multiple uses. Currently, camelina is not used as a cover crop, but it has the potential to be used as such in maize-soybean-wheat cropping systems. The objectives of this study were to determine the agronomic performance and nutrient scavenging potential of winter camelina in comparison with other common cover crops. Experiments were conducted in Fargo, ND in 2015 and 2016, and in Prosper, ND in 2015. The experimental design was a randomized complete block design with a split-plot arrangement with three replicates. The main plot was the sowing date and the subplot were camelina cultivars as well as other common cover crops in the area. Sowing dates were targeted to 15 August and September 1, although the final dates varied slightly each year. Biomass yield, N content of the biomass N uptake and P uptake was evaluated. Winter camelina N and P uptake ranged between 21 and 30.5 kg N ha-1 and 3.4 to 5.3 kg P ha-1. The nutrient scavenging potential of winter camelina was similar to other cover crops although slightly lower than turnip (Brassica rapa L.), radish (Raphanus sativus L.), and rape (Brassica napus L.) cultivars which had significantly higher P uptake than winter camelina and the other cover crops in the study. An evaluation of spring regrowth and cover indicated that only rye, winter camelina, and pennycress (Thlaspi arvense L.) survived the winter, although a few plants of triticale (x Trticosecale Witt.) and rape were found on a few plots. Because of the high variability on the plots there were no significant differences among the surviving cover crops on soil coverage. The soil coverage for rye cultivars was 25 and 35% and for camelina cv. Bison was 27%.In 2016, biomass yield was not significant for sowing date, cultivars, or their interaction. Winter camelina cultivars biomass yield fluctuated between 1.15 and 2.33 Mg dry matter ha-1 on the first sowing

  16. Richness, biomass, and nutrient content of a wetland macrophyte community affect soil nitrogen cycling in a diversity-ecosystem functioning experiment

    Science.gov (United States)

    Korol, Alicia R.; Ahn, Changwoo; Noe, Gregory

    2016-01-01

    The development of soil nitrogen (N) cycling in created wetlands promotes the maturation of multiple biogeochemical cycles necessary for ecosystem functioning. This development proceeds from gradual changes in soil physicochemical properties and influential characteristics of the plant community, such as competitive behavior, phenology, productivity, and nutrient composition. In the context of a 2-year diversity experiment in freshwater mesocosms (0, 1, 2, 3, or 4 richness levels), we assessed the direct and indirect impacts of three plant community characteristics – species richness, total biomass, and tissue N concentration – on three processes in the soil N cycle – soil net ammonification, net nitrification, and denitrification potentials. Species richness had a positive effect on net ammonification potential (NAP) through higher redox potentials and likely faster microbial respiration. All NAP rates were negative, however, due to immobilization and high rates of ammonium removal. Net nitrification was inhibited at higher species richness without mediation from the measured soil properties. Higher species richness also inhibited denitrification potential through increased redox potential and decreased nitrification. Both lower biomass and/or higher tissue ratios of carbon to nitrogen, characteristics indicative of the two annual plants, were shown to have stimulatory effects on all three soil N processes. The two mediating physicochemical links between the young macrophyte community and microbial N processes were soil redox potential and temperature. Our results suggest that early-successional annual plant communities play an important role in the development of ecosystem N multifunctionality in newly created wetland soils.

  17. Bacterial Active Community Cycling in Response to Solar Radiation and Their Influence on Nutrient Changes in a High-Altitude Wetland.

    Science.gov (United States)

    Molina, Verónica; Hernández, Klaudia; Dorador, Cristina; Eissler, Yoanna; Hengst, Martha; Pérez, Vilma; Harrod, Chris

    2016-01-01

    Microbial communities inhabiting high-altitude spring ecosystems are subjected to extreme changes in solar irradiance and temperature throughout the diel cycle. Here, using 16S rRNA gene tag pyrosequencing (cDNA) we determined the composition of actively transcribing bacteria from spring waters experimentally exposed through the day (morning, noon, and afternoon) to variable levels of solar radiation and light quality, and evaluated their influence on nutrient recycling. Solar irradiance, temperature, and changes in nutrient dynamics were associated with changes in the active bacterial community structure, predominantly by Cyanobacteria, Verrucomicrobia, Proteobacteria, and 35 other Phyla, including the recently described Candidate Phyla Radiation (e.g., Parcubacteria, Gracilibacteria, OP3, TM6, SR1). Diversity increased at noon, when the highest irradiances were measured (3.3-3.9 H', 1125 W m -2 ) compared to morning and afternoon (0.6-2.8 H'). This shift was associated with a decrease in the contribution to pyrolibraries by Cyanobacteria and an increase of Proteobacteria and other initially low frequently and rare bacteria phyla (solar radiation. In addition, the percentage contribution of cyanobacterial sequences in the afternoon was similar to those recorded in the morning. The shifts in the contribution by Cyanobacteria also influenced the rate of change in nitrate, nitrite, and phosphate, highlighted by a high level of nitrate accumulation during hours of high radiation and temperature associated with nitrifying bacteria activity. We did not detect ammonia or nitrite oxidizing bacteria in situ , but both functional groups ( Nitrosomona and Nitrospira ) appeared mainly in pyrolibraries generated from dark incubations. In total, our results reveal that both the structure and the diversity of the active bacteria community was extremely dynamic through the day, and showed marked shifts in composition that influenced nutrient recycling, highlighting how abiotic

  18. Life cycle assessment of different strategies for energy and nutrient recovery from source sorted organic fraction of household waste

    DEFF Research Database (Denmark)

    Khoshnevisan, Benyamin; Tsapekos, Panagiotis; Alvarado-Morales, Merlin

    2018-01-01

    This study attempted to apply life cycle assessment (LCA) methodology to compare distinctive management strategies when biologically treating source-sorted organic household waste (SSOHW). The management strategies included different pretreatment methods of SSOHW prior to anaerobic digestion...... obtained, it can be concluded that CHP production would be the best downstream management option while the results were so sensitive to the source of substituted energy....

  19. Produção de serapilheira e ciclagem de nutrientes na cultura do cajueiro anão precoce Litter production and nutrient cycles in the young dwarf cashew culture

    Directory of Open Access Journals (Sweden)

    Ismail Soares

    2008-02-01

    decomposição das folhas.This study aimed to (a to evaluate the biomass production from the crown of the young dwarf cashew, clone CCP 76, at 2, 3, 8 and 9 years of culture implantation, (b to determine the rate of leaf decomposition and (c to quantify nutrient contribution potentially available in the biomass to be recycled into the soil. The research was conducted at the Experimental Field of Curu, in Paraipaba - CE, from December, 2003 to January, 2005. The treatments consisted of orchards with trees of 2, 3, 8 and 9 years of plantation, distributed in a completely randomized design with eight replications. Litter was collected using 1 m² collectors with 1 mm² mesh place 40 cm above the soil surface. After sampling, the material was sorted out into portions of leaves, branches, inflorescence, peduncle and nut, oven dried and weighed. In the leaf portion, the compositions of N, P, K, Ca, Mg, S, Na, Cu, Fe, Mn and Zn were determined. Leaves ready to fall were collected from each plant to determine their decomposition rate and 12 g of this material was stove dried, and placed in 20 cm x 20 cm nylon bags and 2 mm mesh which were distributed on the soil surface and collected after 112, 233 and 369 days. In each collection, the material was oven dried and the remaining nutrient biomass (N, P, K, Ca, Mg, S, Na, Cu, Fe, Mn and Zn was determined. The 8- and 9- year- old plants deposited greater quantities of litter during the experimental period and showed greater potential for nutrient recycling. During the experimental period it was generally observed that the decomposition process was fast in the first four months, remaining slow until the end of the observation period. Most of the nutrients in the cashew tree were released in the first four months of leaf composition.

  20. Nutrient-cycling microbes in coastal Douglas-fir forests: regional-scale correlation between communities, in situ climate, and other factors.

    Science.gov (United States)

    Shay, Philip-Edouard; Winder, Richard S; Trofymow, J A

    2015-01-01

    Microbes such as fungi and bacteria play fundamental roles in litter-decay and nutrient-cycling; however, their communities may respond differently than plants to climate change. The structure (diversity, richness, and evenness) and composition of microbial communities in climate transects of mature Douglas-fir stands of coastal British Columbia rainshadow forests was analyzed, in order to assess in situ variability due to different temperature and moisture regimes. We compared denaturing gradient gel electrophoresis profiles of fungi (18S-FF390/FR1), nitrogen-fixing bacteria (NifH-universal) and ammonia-oxidizing bacteria (AmoA) polymerase chain reaction amplicons in forest floor and mineral soil samples from three transects located at different latitudes, each transect spanning the Coastal Western Hemlock and Douglas-fir biogeoclimatic zones. Composition of microbial communities in both soil layers was related to degree days above 0°C (2725-3489), while pH (3.8-5.5) best explained shifts in community structure. At this spatial scale, climatic conditions were likely to directly or indirectly select for different microbial species while local site heterogeneity influenced community structure. Significant changes in microbial community composition and structure were related to differences as small as 2.47% and 2.55°C in mean annual moisture and temperature variables, respectively. The climatic variables best describing microbial composition changed from one functional group to the next; in general they did not alter community structure. Spatial distance, especially associated with latitude, was also important in accounting for community variability (4-23%); but to a lesser extent than the combined influence of climate and soil characteristics (14-25%). Results suggest that in situ climate can independently account for some patterns of microbial biogeography in coastal Douglas-fir forests. The distribution of up to 43% of nutrient-cycling microorganisms detected in

  1. Life cycle assessment of microalgae-based aviation fuel: Influence of lipid content with specific productivity and nitrogen nutrient effects.

    Science.gov (United States)

    Guo, Fang; Zhao, Jing; A, Lusi; Yang, Xiaoyi

    2016-12-01

    The aim of this work is to compare the life cycle assessments of low-N and normal culture conditions for a balance between the lipid content and specific productivity. In order to achieve the potential contribution of lipid content to the life cycle assessment, this study established relationships between lipid content (nitrogen effect) and specific productivity based on three microalgae strains including Chlorella, Isochrysis and Nannochloropsis. For microalgae-based aviation fuel, the effects of the lipid content on fossil fuel consumption and greenhouse gas (GHG) emissions are similar. The fossil fuel consumption (0.32-0.68MJ·MJ -1 MBAF) and GHG emissions (17.23-51.04gCO 2 e·MJ -1 MBAF) increase (59.70-192.22%) with the increased lipid content. The total energy input decreases (2.13-3.08MJ·MJ -1 MBAF, 14.91-27.95%) with the increased lipid content. The LCA indicators increased (0-47.10%) with the decreased nitrogen recovery efficiency (75-50%). Copyright © 2016 Elsevier Ltd. All rights reserved.

  2. Emissão de fluxos foliares, floração e ciclagem de nutrientes em clones de copa de Hevea pauciflora Fluxes emission of leaves, flowering and nutrient cycling in crown clones of Hevea pauciflora

    Directory of Open Access Journals (Sweden)

    Larissa Alexandra Cardoso Moraes

    2012-09-01

    Full Text Available A fenologia foliar tem sido utilizada como uma característica importante na seleção dos clones de Hevea spp., enquanto o teor de nutrientes na serapilheira é um bom indicador da ciclagem de nutrientes. O objetivo deste trabalho foi verificar o efeito da periodicidade de emissão de fluxos foliares na floração de copa de Hevea pauciflora, estado nutricional e qualidade da serapilheira. Foram avaliadas 15 plantas de 10 anos de idade dos clones de copa CNS G 112, CNS G 124 e CBA 2. Nas condições edafoclimáticas da Amazônia tropical úmida, a emissão de folhas e de floração de H. pauciflora ocorre com maior intensidade no segundo semestre (início do período chuvoso. A H. pauciflora apresenta maior acúmulo de serapilheira que a floresta primária e os teores foliares de 22,18 g kg-1 de N, 1,47 g kg-1 de P, 5,77 g kg-1 de K, 3,79 g kg-1 de Ca, 2,09 g kg-1 de Mg, 16,15 mg kg-1 de B, 6,14 mg kg-1 de Cu, 53,87 mg kg-1 de Fe, 66,20 mg kg-1 de Mn e 48,44 mg kg-1 de Zn podem ser utilizados como referência para essa espécie de seringueira.The leaf phenology has been used as an important characteristic in the selection of Hevea spp. clones, while the nutrient content in litter is a good indicator of nutrient cycling. The objective of this study was to verify the effect of frequency of emission of fluxes of leaves and flowers in crown of Hevea pauciflora, nutritional status and quality of litter. Fifteen plants of ten-year-old of each clones (CNS G 112, CNS G 124 and CBA 2 were evaluated. In tropical Amazonia edaphoclimatic conditions, the leaf emergence and flowering of H. pauciflora occurs with higher intensity in the second semester (beginning of rainy season. The H. pauciflora has higher quantity of litter than the primary forest, and the foliar concentrations of 22.18 g kg-1 of N, 1.47 g kg-1 of P, 5.77 g kg-1 of K, 3.79 g kg-1 de Ca, 2.09 g kg-1 of Mg, 16.15 mg kg-1 of B, 6.14 mg kg-1 of Cu, 53.87 mg kg-1 of Fe, 66.20 mg kg-1 of Mn e 48

  3. Produção de serapilheira e ciclagem de nutrientes de uma floresta estacional semidecidual em zona ripária Litter production and nutrient cycling of a semideciduous mesophytic forest in a riparian zone

    Directory of Open Access Journals (Sweden)

    Ana Rosa Tundis Vital

    2004-12-01

    Full Text Available O presente trabalho foi realizado em uma zona ripária no período de outubro de 2000 a setembro de 2001, em uma parcela representativa de mata ciliar com vegetação do tipo "Floresta Estacional Semidecidual", localizada no centro-sul do Estado de São Paulo. A produção total de serapilheira foi de 10.646,0 kg.ha-1.a-1. A maior deposição de serapilheira e nutrientes ocorreu no fim da estação seca. A transferência total de macronutrientes foi de 217,76 kg.ha-1 de N, 11,55 kg.ha-1 de P, 52,79 kg.ha-1 de K, 199,80 kg.ha-1 de Ca e 38,70 kg.ha-1 de Mg. A serapilheira acumulada foi estimada em 6.227,25 kg.ha-1, a estimativa da taxa instantânea de decomposição (K, de 1,71; e o tempo necessário para o desaparecimento de 50 e 95% da serapilheira produzida, 150 e 639 dias, respectivamente.This work was carried out in a riparian zone from October 2000 to September 2001, within a representative plot of a riparian forest with semideciduous mesophytic forest vegetation, located in the center southern region of São Paulo state. The total litter production was 10.646 kg.ha-1.y-1. The season of highest litter and nutrient deposition was the late dry season. The total macronutrient transfer was 217.76 kg.ha-1 N; 11.55 kg.ha-1 P; 52.79 kg.ha-1 K; 199.80 kg.ha-1 Ca and 38.70 kg.ha-1 Mg. The accumulated litter was estimated as 6.227 kg.ha-1, instantaneous decomposition rate (K 1.71 and time needed time for 50% and 95% litter disappearance was 150 and 639 days, respectively.

  4. Nitrogen deposition may enhance soil carbon storage via change of soil respiration dynamic during a spring freeze-thaw cycle period.

    Science.gov (United States)

    Yan, Guoyong; Xing, Yajuan; Xu, Lijian; Wang, Jianyu; Meng, Wei; Wang, Qinggui; Yu, Jinghua; Zhang, Zhi; Wang, Zhidong; Jiang, Siling; Liu, Boqi; Han, Shijie

    2016-06-30

    As crucial terrestrial ecosystems, temperate forests play an important role in global soil carbon dioxide flux, and this process can be sensitive to atmospheric nitrogen deposition. It is often reported that the nitrogen addition induces a change in soil carbon dioxide emission in growing season. However, the important effects of interactions between nitrogen deposition and the freeze-thaw-cycle have never been investigated. Here we show nitrogen deposition delays spikes of soil respiration and weaken soil respiration. We found the nitrogen addition, time and nitrogen addition×time exerted the negative impact on the soil respiration of spring freeze-thaw periods due to delay of spikes and inhibition of soil respiration (p nitrogen), 39% (medium-nitrogen) and 36% (high-nitrogen) compared with the control. And the decrease values of soil respiration under medium- and high-nitrogen treatments during spring freeze-thaw-cycle period in temperate forest would be approximately equivalent to 1% of global annual C emissions. Therefore, we show interactions between nitrogen deposition and freeze-thaw-cycle in temperate forest ecosystems are important to predict global carbon emissions and sequestrations. We anticipate our finding to be a starting point for more sophisticated prediction of soil respirations in temperate forests ecosystems.

  5. Can algal biotechnology bring effective solution for closing the phosphorus cycle? Use of algae for nutrient removal: Review of past trends and future perspectives in the context of nutrient recovery

    Directory of Open Access Journals (Sweden)

    Kateřina Sukačová

    2017-06-01

    Full Text Available Eutrophication of water by nutrient pollution is a global environmental issue. Biological methods for removing nutrients are environmentally friendly and sustainable. Therefore, this article summarizes main trends in the use of algae for removing nutrients from wastewater using both suspended and attached algal-based systems. A wide variety of algal species and experimental approaches has been tested to date. Researchers report that algae are able to effectively remove a variety of pollutants and nutrients. This review also discusses the potential of algal-based technology for nutrient, especially phosphorus, recovery. Despite the fact that effective nutrient removal has been demonstrated, there are still many challenges to be overcome in the development of succesfull technologies.

  6. Geochemical cycling and depositional patterns across the northeast region of the Greenland Ice Sheet as determined from trace element chemistry

    Science.gov (United States)

    Wong, G. J.; Osterberg, E. C.; Courville, Z.; Hawley, R. L.; Lutz, E.; Overly, T. B.

    2012-12-01

    The Greenland Ice Sheet is both a repository of climate history and a major driver in Arctic and global climate. Between 1952 and 1955, Carl Benson led a series of traverses of the Greenland Ice Sheet (GIS), and characterized the GIS via mapping of the spatial distribution of annual net accumulation and classifying the diagenetic glacier facies (Benson, 1962). While polar ice sheets represent a unique archive of past atmospheric and climatic conditions, little information exists on large-scale geographical trends in trace element snow chemistry across GIS because of the remote, challenging location. In the spring of 2011, we undertook a 1120 km traverse of the GIS from Thule Air Base to Summit Station. Samples from 11 snow pits and 3 firn cores, dated by stable water isotopes, were analyzed and evaluated in seasonal resolution for their trace element content (23Na, 24Mg, 27Al, 32S, 39K, 44Ca, 47Ti, 51V, 52Cr, 55Mn, 56Fe, 59Co, 63Cu, 66Zn, 75As, 88Sr, 111Cd, 133Cs, 138Ba, 139La, 140Ce, 141Pr, 208Pb, 209Bi, 238U). Here, we present an initial analysis of the spatial gradients of these trace elements and an interpretation of how their depositional patterns characterize the GIS. The seasonal trends coupled with spatial variability of certain trace elements establish the behavior of specific aerosols (e.g. dust, sea salt, pollution), which will be useful in quantifying geochemical cycling across the GIS and comparing characterizations with results from Benson's traverses. Benson, CS. 1962. Stratigraphic studies in the snow and firn of the Greenland Ice Sheet. SIPRE Research Report, 70, 89 pp.

  7. Effects of Aridity and Fog Deposition on C3/CAM Photosynthesis and N-cycling in Welwitschia mirabilis

    Science.gov (United States)

    Soderberg, K.; Henschel, J.; Macko, S. A.

    2008-12-01

    Environmental controls on photosynthesis and N-cycling in Welwitschia mirabilis are evaluated through δ13C and δ15N analyses of leaf material from 26 individuals in the southermost population of this long-lived gymnosperm, which is endemic to the Namib Desert. The coastal Namib Desert in southwestern Africa is hyperarid in terms of rainfall, but receives up to 100 days of fog each year. This climate regime leads to interesting water relations in the Namib flora and fauna. Among many enigmatic characteristics, photosynthesis in W. mirabilis has puzzled researchers since the 1970's. Although it is predominantly a C3 plant, δ13C ranges from -17.5 to -23.5‰ in natural habitats, and can be as enriched as -14.4‰ under artificial growing conditions. Recently the CAM pathway has been confirmed, but the driver for CAM utilization has not been identified. In this study we incorporate new δ13C compositions for plants in the middle of the 100 km aridity gradient which spans the natural distribution of W. mirabilis. Initial results show an enriched δ13C signal (-20‰) in the more exposed individuals compared with those in a sandy drainage depression (-22‰). In addition, the documented correlation between rainfall and δ15N found in Kalahari C3 plants (Swap et al. 2004) is used to interpret the δ15N values in this W. mirabilis population. Initial results indicate that the fog deposition may significantly affect the nutrition of these unusual plants from the Namib Desert.

  8. Application of a Hybrid Forest Growth Model to Evaluate Climate Change Impacts on Productivity, Nutrient Cycling and Mortality in a Montane Forest Ecosystem.

    Science.gov (United States)

    Seely, Brad; Welham, Clive; Scoullar, Kim

    2015-01-01

    Climate change introduces considerable uncertainty in forest management planning and outcomes, potentially undermining efforts at achieving sustainable practices. Here, we describe the development and application of the FORECAST Climate model. Constructed using a hybrid simulation approach, the model includes an explicit representation of the effect of temperature and moisture availability on tree growth and survival, litter decomposition, and nutrient cycling. The model also includes a representation of the impact of increasing atmospheric CO2 on water use efficiency, but no direct CO2 fertilization effect. FORECAST Climate was evaluated for its ability to reproduce the effects of historical climate on Douglas-fir and lodgepole pine growth in a montane forest in southern British Columbia, Canada, as measured using tree ring analysis. The model was subsequently used to project the long-term impacts of alternative future climate change scenarios on forest productivity in young and established stands. There was a close association between predicted sapwood production and measured tree ring chronologies, providing confidence that model is able to predict the relative impact of annual climate variability on tree productivity. Simulations of future climate change suggest a modest increase in productivity in young stands of both species related to an increase in growing season length. In contrast, results showed a negative impact on stemwood biomass production (particularly in the case of lodgepole pine) for established stands due to increased moisture stress mortality.

  9. Application of a Hybrid Forest Growth Model to Evaluate Climate Change Impacts on Productivity, Nutrient Cycling and Mortality in a Montane Forest Ecosystem.

    Directory of Open Access Journals (Sweden)

    Brad Seely

    Full Text Available Climate change introduces considerable uncertainty in forest management planning and outcomes, potentially undermining efforts at achieving sustainable practices. Here, we describe the development and application of the FORECAST Climate model. Constructed using a hybrid simulation approach, the model includes an explicit representation of the effect of temperature and moisture availability on tree growth and survival, litter decomposition, and nutrient cycling. The model also includes a representation of the impact of increasing atmospheric CO2 on water use efficiency, but no direct CO2 fertilization effect. FORECAST Climate was evaluated for its ability to reproduce the effects of historical climate on Douglas-fir and lodgepole pine growth in a montane forest in southern British Columbia, Canada, as measured using tree ring analysis. The model was subsequently used to project the long-term impacts of alternative future climate change scenarios on forest productivity in young and established stands. There was a close association between predicted sapwood production and measured tree ring chronologies, providing confidence that model is able to predict the relative impact of annual climate variability on tree productivity. Simulations of future climate change suggest a modest increase in productivity in young stands of both species related to an increase in growing season length. In contrast, results showed a negative impact on stemwood biomass production (particularly in the case of lodgepole pine for established stands due to increased moisture stress mortality.

  10. Nutrients that limit growth in the ocean.

    Science.gov (United States)

    Bristow, Laura A; Mohr, Wiebke; Ahmerkamp, Soeren; Kuypers, Marcel M M

    2017-06-05

    Phytoplankton form the basis of the marine food web and are responsible for approximately half of global carbon dioxide (CO2) fixation (∼ 50 Pg of carbon per year). Thus, these microscopic, photosynthetic organisms are vital in controlling the atmospheric CO2 concentration and Earth's climate. Phytoplankton are dependent on sunlight and their CO2-fixation activity is therefore restricted to the upper, sunlit surface ocean (that is, the euphotic zone). CO2 usually does not limit phytoplankton growth due to its high concentration in seawater. However, the vast majority of oceanic surface waters are depleted in inorganic nitrogen, phosphorus, iron and/or silica; nutrients that limit primary production in the ocean (Figure 1). Phytoplankton growth is mainly supported by either the recycling of nutrients or by reintroduction of nutrients from deeper waters by mixing. A small percentage of primary production, though, is fueled by 'external' or 'new' nutrients and it is these nutrients that determine the amount of carbon that can be sequestered long term in the deep ocean. For most nutrients such as phosphorus, iron, and silica, the external supply is limited to atmospheric deposition and/or coastal and riverine inputs, whereas their main sink is the sedimentation of particulate matter. Nitrogen, however, has an additional, biological source, the fixation of N2 gas, as well as biological sinks via the processes of denitrification and anammox. Despite the comparatively small contributions to the overall turnover of nutrients in the ocean, it is these biological processes that determine the ocean's capacity to sequester CO2 from the atmosphere on time scales of ocean circulation (∼ 1000 years). This primer will highlight shifts in the traditional paradigms of nutrient limitation in the ocean, with a focus on the uniqueness of the nitrogen cycling and its biological sources and sinks. Copyright © 2017 Elsevier Ltd. All rights reserved.

  11. Impact of harvesting and atmospheric pollution on nutrient depletion of eastern US hardwood forests

    Science.gov (United States)

    M.B. Adams; J.A. Burger; A.B. Jenkins; L. Zelazny

    2000-01-01

    The eastern hardwood forests of the US may be threatened by the changing atmospheric chemistry and by changes in harvesting levels. Many studies have documented accelerated base cation losses with intensive forest harvesting. Acidic deposition can also alter nutrient cycling in these forests. The combination of increased harvesting, shorter rotations, and more...

  12. Tree growth, foliar chemistry, and nitrogen cycling across a nitrogen deposition gradient in southern Appalachian deciduous forests

    Science.gov (United States)

    Johnny L. Boggs; Steven G. McNulty; Michael J. Gavazzi; Jennifer Moore Myers

    2005-01-01

    The declining health of high-elevation red spruce (Picea rubens Sarg.) and Fraser fir (Abies fraseri (Pursh) Poir.) in the southern Appalachian region has long been linked to nitrogen (N)deposition. Recently, N deposition has also been proposed as a source of negative health impacts in lower elevation deciduous forests. In 1998 we...

  13. Global Economics of Nutrient Cycling

    NARCIS (Netherlands)

    Janssen, B.H.; Oenema, O.

    2008-01-01

    This paper briefly discusses global human requirements of protein nitrogen (N) from crops and animals, and then estimates the need for fertilizer N as a function of N use efficiency, and the recycling of N from animal manure and sewage wastes. These estimates are based on various assumptions and

  14. Molecular Analysis of Flood Deposits in the Tennessee River Valley: Implications for Understanding Carbon Cycling in Fluvial Environments and Anthropogenic Impacts

    Science.gov (United States)

    Blackaby, E.; Craven, O. D.; Hockaday, W. C.; Forman, S. L.; Stinchcomb, G. E.

    2017-12-01

    The middle Tennessee River Valley contains both historic and prehistoric (>AD 1600) flood deposits. Stratigraphic sequences of stacked flood deposits that often bury soils provide new insights on organic matter transported and preserved prior to and after European colonization. This study focused on understanding carbon cycling within a dynamic fluvial system and quantifying the anthropogenic effect on flood processes through the analysis of molecular components of the organic matter. The data may be helpful in discerning the organic geochemical fingerprint for historic and prehistoric flood deposits. Ten samples were collected from three sites at varying depths and dated using optically stimulated luminescence (OSL). All samples underwent solid-state cross polar 13C NMR analysis at twelve kilohertz, and a molecular mixing model (MMM) was used to determine the molecular components of the organic matter present in each sample. The MMM categorized carbon molecules present in each sample in terms of carbohydrate, protein, lipid, lignin, char, or pure carbonyl. Char was the most prominent molecular component of all ten samples ranging from 28.7 to 55.9% and comprised larger percentages in prehistoric deposits. The historic deposits, while still char dominated, showed more molecular diversity with higher percentages in non-char carbon groups. The carbonyl, lipid, and carbohydrate groups are present throughout all the samples with the carbonyl ranging from 9.3 to 31.4%, the lipid from 5.5 to 16.7%, and the carbohydrate from 4.4 to 16.9%. The high amount of carbonyl throughout the samples indicates that the deposits existed in a highly oxidizing environment. Differences in the presence and amount of carbon groups between historic and prehistoric flood deposits potentially reflect diagenic alternation of organic matter through time, changes in human land use, or some combination processes. These preliminary results possibly indicate changes in carbon pools accessed with

  15. Leucine Aminopeptidase, β-Glucosidase and Alkaline Phosphatase Activity Rates and Their Significance in Nutrient Cycles in Some Coastal Mediterranean Sites

    Directory of Open Access Journals (Sweden)

    Gabriella Caruso

    2010-03-01

    Full Text Available In aquatic microbial ecology, knowledge of the processes involved in the turnover of organic matter is of utmost importance to understand ecosystem functioning. Microorganisms are major players in the cycling of nutrients (nitrogen, phosphorus and carbon, thanks to their enzymatic activities (leucine aminopeptidase, LAP, alkaline phosphatase, AP, and β-glucosidase, β-GLU on organic polymers (proteins, organic phosphates and polysaccharides, respectively. Estimates of the decomposition rates of organic polymers are performed using fluorogenic compounds, whose hydrolysis rate allow us to obtain information on the “potential” metabolic activity of the prokaryotic community. This paper refers the enzyme patterns measured during recent oceanographic cruises performed in some coastal Mediterranean sites, not yet fully investigated in terms of microbial biogeochemical processes. Mean enzyme activity rates ranged from 5.24 to 5558.1 nM/h, from 12.68 to 244.73 nM/h and from 0.006 to 9.51 nM/h for LAP, AP and β-GLU, respectively. The highest LAP and AP activity rates were measured in the Gulf of Milazzo (Tyrrhenian Sea and in the Straits of Messina, in association with the lowest bacterioplankton abundance; in contrast, the lowest ones were found in the northern Adriatic Sea. β-GLU was more active in the Straits of Messina. Activity rates were analysed in relation to the main environmental variables. Along the northern Adriatic coastal side affected by the Po river, significant inverse relationships linked LAP and AP with salinity, pointing out that fluvial inputs provided organic substrates for microbial metabolism. Both in the Gulf of Manfredonia and in the Straits of Messina, LAP and AP levels were inversely related with the concentration of nitrate and inorganic phosphorus, respectively. In the Gulf of Milazzo, high cell-specific AP measured in spite of phosphorus availability suggested the role of this enzyme not only in phosphorus, but also

  16. Leucine aminopeptidase, beta-glucosidase and alkaline phosphatase activity rates and their significance in nutrient cycles in some coastal Mediterranean sites.

    Science.gov (United States)

    Caruso, Gabriella

    2010-03-29

    In aquatic microbial ecology, knowledge of the processes involved in the turnover of organic matter is of utmost importance to understand ecosystem functioning. Microorganisms are major players in the cycling of nutrients (nitrogen, phosphorus) and carbon, thanks to their enzymatic activities (leucine aminopeptidase, LAP, alkaline phosphatase, AP, and beta-glucosidase, beta-GLU) on organic polymers (proteins, organic phosphates and polysaccharides, respectively). Estimates of the decomposition rates of organic polymers are performed using fluorogenic compounds, whose hydrolysis rate allow us to obtain information on the "potential" metabolic activity of the prokaryotic community. This paper refers the enzyme patterns measured during recent oceanographic cruises performed in some coastal Mediterranean sites, not yet fully investigated in terms of microbial biogeochemical processes. Mean enzyme activity rates ranged from 5.24 to 5558.1 nM/h, from 12.68 to 244.73 nM/h and from 0.006 to 9.51 nM/h for LAP, AP and beta-GLU, respectively. The highest LAP and AP activity rates were measured in the Gulf of Milazzo (Tyrrhenian Sea) and in the Straits of Messina, in association with the lowest bacterioplankton abundance; in contrast, the lowest ones were found in the northern Adriatic Sea. beta-GLU was more active in the Straits of Messina. Activity rates were analysed in relation to the main environmental variables. Along the northern Adriatic coastal side affected by the Po river, significant inverse relationships linked LAP and AP with salinity, pointing out that fluvial inputs provided organic substrates for microbial metabolism. Both in the Gulf of Manfredonia and in the Straits of Messina, LAP and AP levels were inversely related with the concentration of nitrate and inorganic phosphorus, respectively. In the Gulf of Milazzo, high cell-specific AP measured in spite of phosphorus availability suggested the role of this enzyme not only in phosphorus, but also in carbon

  17. Leucine Aminopeptidase, β-Glucosidase and Alkaline Phosphatase Activity Rates and Their Significance in Nutrient Cycles in Some Coastal Mediterranean Sites

    Science.gov (United States)

    Caruso, Gabriella

    2010-01-01

    In aquatic microbial ecology, knowledge of the processes involved in the turnover of organic matter is of utmost importance to understand ecosystem functioning. Microorganisms are major players in the cycling of nutrients (nitrogen, phosphorus) and carbon, thanks to their enzymatic activities (leucine aminopeptidase, LAP, alkaline phosphatase, AP, and β-glucosidase, β-GLU) on organic polymers (proteins, organic phosphates and polysaccharides, respectively). Estimates of the decomposition rates of organic polymers are performed using fluorogenic compounds, whose hydrolysis rate allow us to obtain information on the “potential” metabolic activity of the prokaryotic community. This paper refers the enzyme patterns measured during recent oceanographic cruises performed in some coastal Mediterranean sites, not yet fully investigated in terms of microbial biogeochemical processes. Mean enzyme activity rates ranged from 5.24 to 5558.1 nM/h, from 12.68 to 244.73 nM/h and from 0.006 to 9.51 nM/h for LAP, AP and β-GLU, respectively. The highest LAP and AP activity rates were measured in the Gulf of Milazzo (Tyrrhenian Sea) and in the Straits of Messina, in association with the lowest bacterioplankton abundance; in contrast, the lowest ones were found in the northern Adriatic Sea. β-GLU was more active in the Straits of Messina. Activity rates were analysed in relation to the main environmental variables. Along the northern Adriatic coastal side affected by the Po river, significant inverse relationships linked LAP and AP with salinity, pointing out that fluvial inputs provided organic substrates for microbial metabolism. Both in the Gulf of Manfredonia and in the Straits of Messina, LAP and AP levels were inversely related with the concentration of nitrate and inorganic phosphorus, respectively. In the Gulf of Milazzo, high cell-specific AP measured in spite of phosphorus availability suggested the role of this enzyme not only in phosphorus, but also in carbon

  18. Nutrients and clam contamination by Escherichia coli in a meso-tidal coastal lagoon: Seasonal variation in counter cycle to external sources

    International Nuclear Information System (INIS)

    Botelho, Maria João; Soares, Florbela; Matias, Domitília; Vale, Carlos

    2015-01-01

    Highlights: • Sources of nutrients and E. coli in Ria Formosa linked to tourism in summer. • Lower nutrient values and clam contamination by E. coli in summer. • Bactericide effect of temperature and solar radiation causes lower E. coli. • Higher biological consumption of nutrients in warmer periods. • Results mirror possible effects of climate changes on coastal lagoons. - Abstract: The clam Ruditapes decussatus was transplanted from a natural recruitment area of Ria Formosa to three sites, surveyed for nutrients in water and sediments. Specimens were sampled monthly for determination of Escherichia coli, condition index and gonadal index. Higher nutrient values in low tide reflect drainage, anthropogenic sources or sediment regeneration, emphasising the importance of water mixing in the entire lagoon driven by the tide. Despite the increase of effluent discharges in summer due to tourism, nutrient concentrations and E. coli in clams were lower in warmer periods. The bactericide effect of temperature and solar radiation was better defined in clams from the inlet channel site than from sites closer to urban effluents. High temperature in summer and torrential freshwater inputs to Ria Formosa may anticipate climate change scenarios for south Europe. Seasonal variation of nutrients and clam contamination may thus point to possible alterations in coastal lagoons and their ecosystem services

  19. RETRACTED ARTICLE: Studies of Microtexture and Its Effect on Tensile and High-Cycle Fatigue Properties of Laser-Powder-Deposited INCONEL 718

    Science.gov (United States)

    Qi, Huan; Azer, Magdi; Deal, Andrew

    2012-11-01

    The current work studies the microstructure, texture, and mechanical properties of INCONEL 718 alloy (IN718) produced by laser direct metal deposition. The grain microstructure exhibits an alternative distribution of banded fine and coarse grain zones as a result of the rastering scanning pattern. The effects of the anisotropic crystallographic texture on the tensile and high-cycle fatigue (HCF) properties at room temperature are investigated. Tensile test results showed that the tensile strength of laser-deposited IN718 after direct aging or solution heat treatment is equivalent to the minimum-forged IN718 properties. The transverse direction (relative to the laser scanning direction) produces >10 pct stiffer modulus of elasticity but 3 to 6 pct less tensile strength compared to the longitudinal direction due to the preferential alignment of grains having and directions parallel to the tensile loading direction. Laser-deposited IN718 with good metallurgical integrity showed equivalent HCF properties compared to the direct-aged wrought IN718, which can be attributed to the banded grain size variation and cyclic change of inclining grain orientations resulted from alternating rastering deposition path.

  20. Modelling the response of soil and runoff chemistry to forest harvesting in a low deposition area (Kangasvaara, eastern Finland

    Directory of Open Access Journals (Sweden)

    J. Kämäri

    1998-01-01

    Full Text Available A simple dynamic soil model developed to analyse the effects of atmospheric deposition and nutrient cycling on terrestrial ecosystems, SMART 2, was applied to the Kangasvaara catchment in eastern Finland. Given the historical deposition and forest growth patterns and reasonable values for the input parameters, SMART 2 was calibrated successfully to reproduce present-day soil and Kangasvaara catchment on the soil and runoff water chemistry under a future deposition scenario (GRP scenario. These impacts were also compared to the effects of further reducing the deposition of sulphur and nitrate under the maximum feasible reduction (MFR scenario. The model demonstrates the consequences of breaking the nutrient cycle, and predicts that final cutting results in increased leaching of inorganic nitrogen and base cations from the cut part of the catchment for about 10 years. The resulting concentrations in the stream will depend on the ability of the buffer zones surrounding the stream to capture and utilize these nutrients.

  1. The effects of a changing pollution climate on throughfall deposition and cycling in a forested area in southern England.

    Science.gov (United States)

    Skeffington, R A; Hill, T J

    2012-09-15

    This study compares two sets of measurements of the composition of bulk precipitation and throughfall at a site in southern England with a 20-year gap between them. During this time, SO(2) emissions from the UK fell by 82%, NO(x) emissions by 35% and NH(3) emissions by 7%. These reductions were partly reflected in bulk precipitation, with deposition reductions of 56% in SO(4)(2-), 38% in NO(3)(-), 32% in NH(4)(+), and 73% in H(+). In throughfall under Scots pine, the effects were more dramatic, with an 89% reduction in SO(4)(2-) deposition and a 98% reduction in H(+) deposition. The mean pH under these trees increased from 2.85 to 4.30. Nitrate and ammonium deposition in throughfall increased slightly, however. In the earlier period, the Scots pines were unable to neutralise the high flux of acidity associated with sulphur deposition, even though this was not a highly polluted part of the UK, and deciduous trees (oak and birch) were only able to neutralise it in summer when the leaves were present. In the later period, the sulphur flux had reduced to the point where the acidity could be neutralised by all species - the neutralisation mechanism is thus likely to be largely leaching of base cations and buffering substances from the foliage. The high fluxes are partly due to the fact that these are 60-80 year old trees growing in an open forest structure. The increase in NO(3)(-) and NH(4)(+) in throughfall in spite of decreased deposition seems likely due to a decrease in foliar uptake, perhaps due to the increasing nitrogen saturation of the catchment soils. These changes may increase the rate of soil microbial activity as nitrogen increases and acidity declines, with consequent effects on water quality of the catchment drainage stream. Copyright © 2011 Elsevier B.V. All rights reserved.

  2. Diagnosing oceanic nutrient deficiency

    Science.gov (United States)

    Moore, C. Mark

    2016-11-01

    The supply of a range of nutrient elements to surface waters is an important driver of oceanic production and the subsequent linked cycling of the nutrients and carbon. Relative deficiencies of different nutrients with respect to biological requirements, within both surface and internal water masses, can be both a key indicator and driver of the potential for these nutrients to become limiting for the production of new organic material in the upper ocean. The availability of high-quality, full-depth and global-scale datasets on the concentrations of a wide range of both macro- and micro-nutrients produced through the international GEOTRACES programme provides the potential for estimation of multi-element deficiencies at unprecedented scales. Resultant coherent large-scale patterns in diagnosed deficiency can be linked to the interacting physical-chemical-biological processes which drive upper ocean nutrient biogeochemistry. Calculations of ranked deficiencies across multiple elements further highlight important remaining uncertainties in the stoichiometric plasticity of nutrient ratios within oceanic microbial systems and caveats with regards to linkages to upper ocean nutrient limitation. This article is part of the themed issue 'Biological and climatic impacts of ocean trace element chemistry'.

  3. Can algal biotechnology bring effective solution for closing the phosphorus cycle? Use of algae for nutrient removal – review of past trends and future perspectives in the context of nutrient recovery

    Czech Academy of Sciences Publication Activity Database

    Sukačová, Kateřina; Červený, Jan

    2017-01-01

    Roč. 7, č. 1 (2017), s. 63-72 ISSN 1805-0174 R&D Projects: GA MŠk(CZ) LO1415 Institutional support: RVO:67179843 Keywords : wastewater treatment * algae * nutrients removal * phosphorus recovery Subject RIV: EH - Ecology, Behaviour OBOR OECD: Environmental sciences (social aspects to be 5.7)

  4. Insects, infestations and nutrient fluxes

    Science.gov (United States)

    Michalzik, B.

    2012-04-01

    endemic situations (Larrson and Tenow 1980). However, at times of insect mass outbreaks with leaf area losses up to 100%, nutrient fluxes are strongly affected at the ecosystem level and consequently attract greater attention (Grace 1986). In this context, mass outbreaks of herbivore insects constitute a class of ecosystem disturbance (Pickett and White 1985). More specific, insect pests meet the criteria of biogeochemical "hot spots" and "hot moments" (McClain et al. 2003) as they induce temporal-spatial process heterogeneity or changes in biogeochemical reaction rates, but not necessarily changes in the structure of ecosystems or landscapes. This contribution presents a compilation of literature and own research data on insect herbivory effects on nutrient cycling and ecosystem functioning from the plot to the catchment scale. It focuses on temperate forest ecosystems and on short-term impacts as exerted by two focal functional groups of herbivore canopy insects (leaf and sap feeders). In detail, research results on effects operating on short temporal scales are presented including a) alterations in throughfall fluxes encompassing dissolved and particulate organic matter fractions, b) alterations in the amount, timing and quality of frass and honeydew deposition and c) soil microbial activity and decomposition processes.

  5. Improvement in high-voltage and high rate cycling performance of nickel-rich layered cathode materials via facile chemical vapor deposition with methane

    International Nuclear Information System (INIS)

    Hyuk Son, In; Park, Kwangjin; Hwan Park, Jong

    2017-01-01

    Nickel-rich layered-oxide materials are considered promising candidates for application as cathode material in high-energy lithium ion batteries. However, their cycling performance at high voltages and rate conditions require further improvement for the purpose of commercialization. Here, we report on the facile surface modification of nickel-rich layered oxide by chemical vapor deposition with methane which yields a conductive and protective artificial solid electrolyte interphase layer consisting of amorphous carbon, alkyl lithium carbonate, and lithium carbonate. We examine the mechanism of the protective layer formation and structural deformation of the nickel-rich layered oxide during chemical vapor deposition with methane. Via optimizing the reaction conditions, we improve the electrical conductivity as well as the interfacial stability of the nickel-rich layered oxide without inducing structural deformation. The surface-modified nickel-rich layered oxide exhibits an improved performance due to the resulting enhanced rate capability, high initial efficiency, and long cycle life at high voltage (>4.5 V).

  6. Modeling long-term changes in tundra carbon balance following wildfire, climate change, and potential nutrient addition.

    Science.gov (United States)

    Jiang, Yueyang; Rastetter, Edward B; Shaver, Gaius R; Rocha, Adrian V; Zhuang, Qianlai; Kwiatkowski, Bonnie L

    2017-01-01

    To investigate the underlying mechanisms that control long-term recovery of tundra carbon (C) and nutrients after fire, we employed the Multiple Element Limitation (MEL) model to simulate 200-yr post-fire changes in the biogeochemistry of three sites along a burn severity gradient in response to increases in air temperature, CO 2 concentration, nitrogen (N) deposition, and phosphorus (P) weathering rates. The simulations were conducted for severely burned, moderately burned, and unburned arctic tundra. Our simulations indicated that recovery of C balance after fire was mainly determined by the internal redistribution of nutrients among ecosystem components (controlled by air temperature), rather than the supply of nutrients from external sources (e.g., nitrogen deposition and fixation, phosphorus weathering). Increases in air temperature and atmospheric CO 2 concentration resulted in (1) a net transfer of nutrient from soil organic matter to vegetation and (2) higher C : nutrient ratios in vegetation and soil organic matter. These changes led to gains in vegetation biomass C but net losses in soil organic C stocks. Under a warming climate, nutrients lost in wildfire were difficult to recover because the warming-induced acceleration in nutrient cycles caused further net nutrient loss from the system through leaching. In both burned and unburned tundra, the warming-caused acceleration in nutrient cycles and increases in ecosystem C stocks were eventually constrained by increases in soil C : nutrient ratios, which increased microbial retention of plant-available nutrients in the soil. Accelerated nutrient turnover, loss of C, and increasing soil temperatures will likely result in vegetation changes, which further regulate the long-term biogeochemical succession. Our analysis should help in the assessment of tundra C budgets and of the recovery of biogeochemical function following fire, which is in turn necessary for the maintenance of wildlife habitat and tundra

  7. Impact of sludge deposition on biodiversity.

    Science.gov (United States)

    Manzetti, Sergio; van der Spoel, David

    2015-11-01

    Sludge deposition in the environment is carried out in several countries. It encompasses the dispersion of treated or untreated sludge in forests, marsh lands, open waters as well as estuarine systems resulting in the gradual accumulation of toxins and persistent organic compounds in the environment. Studies on the life cycle of compounds from sludge deposition and the consequences of deposition are few. Most reports focus rather on treatment-methods and approaches, legislative aspects as well as analytical evaluations of the chemical profiles of sludge. This paper reviews recent as well as some older studies on sludge deposition in forests and other ecosystems. From the literature covered it can be concluded that sludge deposition induces two detrimental effects on the environment: (1) raising of the levels of persistent toxins in soil, vegetation and wild life and (2) slow and long-termed biodiversity-reduction through the fertilizing nutrient pollution operating on the vegetation. Since recent studies show that eutrophication of the environment is a major threat to global biodiversity supplying additional nutrients through sludge-based fertilization seems imprudent. Toxins that accumulate in the vegetation are transferred to feeding herbivores and their predators, resulting in a reduced long-term survival chance of exposed species. We briefly review current legislation for sludge deposition and suggest alternative routes to handling this difficult class of waste.

  8. A canopy trimming experiment in Puerto Rico: The response of litter decomposition and nutrient release to canopy opening and debris deposition in a subtropical wet forest

    Science.gov (United States)

    G. Gonzalez; D.J. Lodge; B.A. Richardson; M.J. Richardson

    2014-01-01

    In this study, we used a replicated factorial design to separate the individual and interacting effects of two main components of a severe hurricane – canopy opening and green debris deposition on leaf litter decay in the tabonuco forest in the Luquillo Mountains of Puerto Rico. We quantify changes in percent mass remaining (PMR), the concentration and absolute amounts...

  9. Effect of wet depositions on losses of nutrients from soil on deforested areas in the Moravian-Silesian Beskids Mts. (the Czech Republic)

    Czech Academy of Sciences Publication Activity Database

    Fiala, Karel; Tůma, Ivan; Holub, P.

    2001-01-01

    Roč. 20, č. 4 (2001), s. 373-381 ISSN 1335-342X R&D Projects: GA ČR GA526/97/0170 Institutional research plan: CEZ:AV0Z6005908 Keywords : wet depositions * deforested area * Moravian-Silesian Beskids Mts. Subject RIV: EF - Botanics Impact factor: 0.192, year: 2001

  10. Reallocation and nutrient use efficiency in Antioquia central forests

    International Nuclear Information System (INIS)

    Leon Pelaez, Juan; Gonzalez Hernandez, Maria; Gallardo Lancho, Juan

    2009-01-01

    We have studied nutrient related variables such as reallocation, nutrient use efficiency (NUE) and fine litter fall for three years in an oak forest Quercus humboldtii Bonpl. and also in some other forest plantations like pine, Pinus patula, and cypress, Cupressus lusitanica, in Antioquia, Colombia. Leaf litter quantities returned to the soil followed a falling sequence: oak (5313.3 kg ha-1 year-1) > pine (4866.5 kg ha-1 year-1) > cypress (2460.3 kg ha-1 year-1). The coniferous species showed the highest NUE for the majority of elements that were examined, except for P, which reached its absolute maximum in the oak forest -where a clear reallocation of this nutrient was also recorded-, probably because of its reduced availability in these volcanic ash-derived soils. Nutrient reallocation allows the conservation of the nutrients by reducing its loss from leaching and litter-fall, thereby closing the nutrient cycle in this native forest. In fact, P gains from net deposition were found there -this includes foliar leaching and atmospheric deposition-, which indicates that the species absorbs the P contained in rainfall from the leaves before it reaches the forest ground. N slow-efficiency use was probably due to its low availability in soil, given its low mineralization rates in these montane forests. K showed the highest reallocation values. Such figures are influenced by its clearly mobile character, according to the highest net deposition levels also verified for this element. With the exception of Mg, there was no clear relationship between the reallocation process and NUE.

  11. Distribución de nitrógeno, fósforo y azufre en un cultivo de colza: efectos sobre el ciclado de nutrientes Distribution of nitrogen, phosphorus and sulfur in oilseed rape: effects on nutrient cycling

    Directory of Open Access Journals (Sweden)

    Gerardo Rubio

    2007-12-01

    Full Text Available Comparado con otros cultivos, la colza tiene una alta demanda de azufre (S por lo que sería esperable que la inclusión de este cultivo en la rotación agrícola acelere el agotamiento de este nutriente en los suelos de las áreas cultivadas. En este trabajo, se comparan los patrones de partición de biomasa, S, nitrógeno (N y fósforo (P en plantas maduras de colza. La información a obtener es relevante desde el punto de vista del ciclado de nutrientes. Para ello se realizó un experimento de campo que se ajustó a un arreglo factorial con dos factores (N y S. En el momento de la cosecha, se midió la acumulación de biomasa, N, P y S en tres compartimientos: granos, rastrojo (resto de parte aérea y raíces. Aunque el rendimiento fue afectado levemente por la adición individual de N o S, la simultánea adición de ambos nutrientes provocó un incremento del 56%. El N y el P presentaron una distribución semejante entre los órganos de la planta estudiados, sin embargo, el S difirió marcadamente de ambos. Su partición al órgano que se exporta (granos fue de menor magnitud que la observada para N y P. En cambio, su partición al rastrojo en pie fue mayor. Esta característica atenuaría los efectos de la alta demanda de S sobre la exportación del cultivo y permitiría una reutilización del fertilizante agregado por el cultivo siguiente.Oilseed rape poses a higher sulfur (S demand, compared to other crops. This may indicate that the inclusion of this crop in the crop rotation could accelerate soil S depletion. In this work, we compared the allocation of biomass, nitrogen (N, phosphorus (P and S in oilseed rape mature plants. Two factors were analyzed in a field experiment: nitrogen and sulphur (two levels for each factor. At harvest, we measured the accumulation of biomass, N, P and S in three compartments: roots, straw and grains. Yield was little affected by the addition of single nutrients but the simultaneous addition of N and S

  12. Vegetation composition, nutrient, and sediment dynamics along a floodplain landscape

    Science.gov (United States)

    Rybicki, Nancy B.; Noe, Gregory; Hupp, Cliff R.; Robinson, Myles

    2015-01-01

    Forested floodplains are important landscape features for retaining river nutrients and sediment loads but there is uncertainty in how vegetation influences nutrient and sediment retention. In order to understand the role of vegetation in nutrient and sediment trapping, we quantified species composition and the uptake of nutrients in plant material relative to landscape position and ecosystem attributes in an urban, Piedmont watershed in Virginia, USA. We investigated in situ interactions among vegetative composition, abundance, carbon (C), nitrogen (N) and phosphorus (P) fluxes and ecosystem attributes such as water level, shading, soil nutrient mineralization, and sediment deposition. This study revealed strong associations between vegetation and nutrient and sediment cycling processes at the plot scale and in the longitudinal dimension, but there were few strong patterns between these aspects at the scale of geomorphic features (levee, backswamp, and toe-slope). Patterns reflected the nature of the valley setting rather than a simple downstream continuum. Plant nutrient uptake and sediment trapping were greatest at downstream sites with the widest floodplain and lowest gradient where the hydrologic connection between the floodplain and stream is greater. Sediment trapping increased in association with higher herbaceous plant coverage and lower tree canopy density that, in turn, was associated with a more water tolerant tree community found in the lower watershed but not at the most downstream site in the watershed. Despite urbanization effects on the hydrology, this floodplain functioned as an efficient nutrient trap. N and P flux rates of herbaceous biomass and total litterfall more than accounted for the N and P mineralization flux rate, indicating that vegetation incorporated nearly all mineralized nutrients into biomass.

  13. Including spatial data in nutrient balance modelling on dairy farms

    Science.gov (United States)

    van Leeuwen, Maricke; van Middelaar, Corina; Stoof, Cathelijne; Oenema, Jouke; Stoorvogel, Jetse; de Boer, Imke

    2017-04-01

    The Annual Nutrient Cycle Assessment (ANCA) calculates the nitrogen (N) and phosphorus (P) balance at a dairy farm, while taking into account the subsequent nutrient cycles of the herd, manure, soil and crop components. Since January 2016, Dutch dairy farmers are required to use ANCA in order to increase understanding of nutrient flows and to minimize nutrient losses to the environment. A nutrient balance calculates the difference between nutrient inputs and outputs. Nutrients enter the farm via purchased feed, fertilizers, deposition and fixation by legumes (nitrogen), and leave the farm via milk, livestock, manure, and roughages. A positive balance indicates to which extent N and/or P are lost to the environment via gaseous emissions (N), leaching, run-off and accumulation in soil. A negative balance indicates that N and/or P are depleted from soil. ANCA was designed to calculate average nutrient flows on farm level (for the herd, manure, soil and crop components). ANCA was not designed to perform calculations of nutrient flows at the field level, as it uses averaged nutrient inputs and outputs across all fields, and it does not include field specific soil characteristics. Land management decisions, however, such as the level of N and P application, are typically taken at the field level given the specific crop and soil characteristics. Therefore the information that ANCA provides is likely not sufficient to support farmers' decisions on land management to minimize nutrient losses to the environment. This is particularly a problem when land management and soils vary between fields. For an accurate estimate of nutrient flows in a given farming system that can be used to optimize land management, the spatial scale of nutrient inputs and outputs (and thus the effect of land management and soil variation) could be essential. Our aim was to determine the effect of the spatial scale of nutrient inputs and outputs on modelled nutrient flows and nutrient use efficiencies

  14. Fate of Deposited Nitrogen in Tropical Forests in Southern China

    DEFF Research Database (Denmark)

    Gurmesa, Geshere Abdisa

    Tropical forests are generally regarded as naturally nitrogen (N)-rich ecosystems where N availability is in excess of biological demands. These forests are usually characterized by increased soil N cycling rates such as mineralization and nitrification causing loss of N through leaching...... nitrogen (N) isotope 15N to uncover two aspects of N cycling in tropical forests: i) the patterns of ecosystem natural 15N abundance (δ15N) in relation to the 15N signature of deposition N, and its response to increased N deposition; ii) the fate of ambient and increased N deposition in the same forests...... and denitrification from the ecosystem. Loss of N, in turn, has many negative consequences, including soil and surface water acidification, plant nutrient imbalances and related adverse effects on biological diversities. Increased atmospheric N deposition that is anticipated for tropical regions may further aggravate...

  15. Extração de nutrientes pelos ramos frutíferos de caquizeiro cultivar giombo durante um ciclo de produção Nutrients uptake by fruitful branches of persimmon cv. giombo in one cycle of production

    Directory of Open Access Journals (Sweden)

    Hideaki Wilson Takahashi

    2010-03-01

    Full Text Available A literatura brasileira apresenta poucos dados para subsidiar a recomendação de adubação para a cultura do caquizeiro, portanto o objetivo deste trabalho foi estudar o acúmulo de massa seca e macronutrientes nos órgãos que compõem o ramo produtivo, ao longo dos estádios fenológicos da cultura de caqui cultivar Giombo e quantificar as necessidades de nutrientes para a produção. O estudo foi realizado em pomar localizado no município de Faxinal-PR, e as amostragens de ramos frutíferos foram iniciadas três semanas após o início da brotação, repetidas a cada três semanas, durante 45 semanas. Foram realizadas análises químicas dos materiais coletados e determinada a extração de nutrientes ao longo do estádio de desenvolvimento. O total de macronutrientes exportados pela colheita dos frutos foram: 25,47; 5.72; 51.53; 6.76; 2.79 e 5,09, respectivamente, para N, P, K, Ca, Mg e S em kg por ha, para produtividade de 27.7 toneladas por ha de fruto, e os exportados pela retirada de ramos podados para fora do pomar, por questões fitossanitárias, foram: 2,1; 0,3; 1,1; 5,8; 0,5 e 0,4 kg de N, P, K, Ca, Mg e S em kg por ha.There is no information supporting fertilization for persimmon crop as far as the Brazilian literature is concerned. Therefore, the goal of this paper was to study the accumulation of dry mass and micronutrient in organs that compounds the productive branch, during phenological growth stages of persimmon cv. Giombo, and to quantify the nutrient requirement for production. The study was carried out in an orchard located in Faxinal-PR. The spacing between plants was 6 x 7 meters. The sampling of fruiting branches started three weeks after budding had begun and this procedure was repeated after every three weeks during 45 weeks. Chemical analyses of the samples were performed and nutrients extractions during phenological growth stages were determinate. The total of macronutrients removed by fruit harvest was 25.47; 5

  16. Dry Matter Production, Nutrient Cycled and Removed, and Soil Fertility Changes in Yam-Based Cropping Systems with Herbaceous Legumes in the Guinea-Sudan Zone of Benin

    Directory of Open Access Journals (Sweden)

    Raphiou Maliki

    2016-01-01

    Full Text Available Traditional yam-based cropping systems (shifting cultivation, slash-and-burn, and short fallow often result in deforestation and soil nutrient depletion. The objective of this study was to determine the impact of yam-based systems with herbaceous legumes on dry matter (DM production (tubers, shoots, nutrients removed and recycled, and the soil fertility changes. We compared smallholders’ traditional systems (1-year fallow of Andropogon gayanus-yam rotation, maize-yam rotation with yam-based systems integrated herbaceous legumes (Aeschynomene histrix/maize intercropping-yam rotation, Mucuna pruriens/maize intercropping-yam rotation. The experiment was conducted during the 2002 and 2004 cropping seasons with 32 farmers, eight in each site. For each of them, a randomized complete block design with four treatments and four replicates was carried out using a partial nested model with five factors: Year, Replicate, Farmer, Site, and Treatment. Analysis of variance (ANOVA using the general linear model (GLM procedure was applied to the dry matter (DM production (tubers, shoots, nutrient contribution to the systems, and soil properties at depths 0–10 and 10–20 cm. DM removed and recycled, total N, P, and K recycled or removed, and soil chemical properties (SOM, N, P, K, and pH water were significantly improved on yam-based systems with legumes in comparison with traditional systems.

  17. New insights in the global cycle of acetonitrile: release from theocean and dry deposition in the tropical savanna of Venezuela

    Directory of Open Access Journals (Sweden)

    E. Sanhueza

    2004-01-01

    Full Text Available Using the proton transfer reaction mass spectrometry (PTR-MS technique, acetonitrile was measured during the wet season in a Venezuelan woodland savanna. The site was located downwind of the Caribbean Sea and no biomass burning events were observed in the region. High boundary layer concentrations of 211±36pmol/mol (median, ±standard deviation were observed during daytime in the well mixed boundary layer, which is about 60pmol/mol above background concentrations recently measured over the Mediterranean Sea and the Pacific Ocean. Most likely acetonitrile is released from the warm waters of the Caribbean Sea thereby enhancing mixing ratios over Venezuela. Acetonitrile concentrations will probably still be much higher in biomass burning plumes, however, the general suitability of acetonitrile as a biomass burning marker should be treated with care. During nights, acetonitrile dropped to levels typically around 120pmol/mol, which is consistent with a dry deposition velocity of 0.14cm/s when a nocturnal boundary layer height of 100m is assumed.

  18. Teores e acúmulo de nutrientes durante o ciclo da mandioquinha-salsa em função da aplicação de nitrogênio, fósforo e potássio Levels and accumulation of nutrients in the cycle of peruvian carrot with application of nitrogen, phosphorus and potassium

    Directory of Open Access Journals (Sweden)

    Adriano Portz

    2006-09-01

    Full Text Available Apesar da cultura da mandioquinha-salsa (Arracacia xanthorrhiza Bancroft ser cultivada há bastante tempo no País, informações referentes aos seus aspectos nutricionais e seu desenvolvimento no campo são ainda incipientes. O estudo dos teores de nutrientes e seu comportamento ao longo do ciclo ontogenético é importante para se estabelecer uma correta recomendação de fertilizantes, níveis críticos e conseqüentemente uma maior produção de raízes comerciais. Com o objetivo de avaliar os teores e o acúmulo de macro e micronutrientes na cultura durante seu desenvolvimento, foi realizado um experimento de campo com três níveis de N, P e K, na região de Nova Friburgo-RJ, utilizando um delineamento experimental de blocos ao acaso com quatro repetições. Foram realizadas quatro amostragens ao longo do ciclo da cultura e coletadas três partes da planta (folhas, propágulo e raízes, observando-se ao longo do tempo o comportamento dos teores e o acúmulo dos nutrientes nessas partes. Não foi observada correlação dos teores de nutrientes nas partes da planta, nas épocas de amostragem, com a produção de raízes comerciais. Maior acúmulo de nutrientes foi observado entre os 150 e 210 DAT nas folhas, aos 210 DAT nos propágulos e aos 300 DAT nas raízes. Os teores foram influenciados pelos tratamentos aplicados no plantio do experimento, mas não foi observada resposta no aumento de produção de raízes comerciais.The arracacha (Arracacia xanthorrhiza Bancroft culture, in spite of already being cultivated for a long time in Brazil, has still low information on its nutritional aspect, and the field development. The study of the nutrient distribution inside the plant and their behavior along the vegetative cycle is important to establish a correct fertilizer recommendation, and to provide nutritional information, besides to obtain best commercial root production. The macro and micro nutrient levels and accumulation in the crop were

  19. Dual RNA-seq transcriptional analysis of wheat roots colonized by Azospirillum brasilense reveals up-regulation of nutrient acquisition and cell cycle genes.

    Science.gov (United States)

    Camilios-Neto, Doumit; Bonato, Paloma; Wassem, Roseli; Tadra-Sfeir, Michelle Z; Brusamarello-Santos, Liziane C C; Valdameri, Glaucio; Donatti, Lucélia; Faoro, Helisson; Weiss, Vinicius A; Chubatsu, Leda S; Pedrosa, Fábio O; Souza, Emanuel M

    2014-05-16

    The rapid growth of the world's population demands an increase in food production that no longer can be reached by increasing amounts of nitrogenous fertilizers. Plant growth promoting bacteria (PGPB) might be an alternative to increase nitrogenous use efficiency (NUE) in important crops such wheat. Azospirillum brasilense is one of the most promising PGPB and wheat roots colonized by A. brasilense is a good model to investigate the molecular basis of plant-PGPB interaction including improvement in plant-NUE promoted by PGPB. We performed a dual RNA-Seq transcriptional profiling of wheat roots colonized by A. brasilense strain FP2. cDNA libraries from biological replicates of colonized and non-inoculated wheat roots were sequenced and mapped to wheat and A. brasilense reference sequences. The unmapped reads were assembled de novo. Overall, we identified 23,215 wheat expressed ESTs and 702 A. brasilense expressed transcripts. Bacterial colonization caused changes in the expression of 776 wheat ESTs belonging to various functional categories, ranging from transport activity to biological regulation as well as defense mechanism, production of phytohormones and phytochemicals. In addition, genes encoding proteins related to bacterial chemotaxi, biofilm formation and nitrogen fixation were highly expressed in the sub-set of A. brasilense expressed genes. PGPB colonization enhanced the expression of plant genes related to nutrient up-take, nitrogen assimilation, DNA replication and regulation of cell division, which is consistent with a higher proportion of colonized root cells in the S-phase. Our data support the use of PGPB as an alternative to improve nutrient acquisition in important crops such as wheat, enhancing plant productivity and sustainability.

  20. Nutrient imbalance in Norway spruce

    International Nuclear Information System (INIS)

    Thelin, Gunnar

    2000-11-01

    The studies presented in my thesis indicate that growing Norway spruce in monoculture does not constitute sustainable forest management in a high N and S deposition environment, such as in southern Sweden. The combination of N-induced high growth rates and leaching due to soil acidification causes soil reserves of nutrients to decrease. This will increase the risk of nutrient imbalance within the trees when nutrient demands are not met. The development of nutrient imbalance in Scania, southern Sweden, was shown as negative trends in needle and soil nutrient status from the mid-80s to the present in Norway spruce and Scots pine stands. This imbalance appears to be connected to high levels of N and S deposition. Clear negative effects on tree vitality were found when using a new branch development method. Today, growth and vitality seems to be limited by K, rather than N, in spruce stands older than 40 years. However, younger stands appear to be able to absorb the deposited N without negative effects on growth and vitality. When investigating effects of nutrient stress on tree vitality, indicators such as branch length and shoot multiplication rate, which include effects accumulated over several years, are suitable. Countermeasures are needed in order to maintain the forest production at a high level. Positive effects on tree nutrient status after vitality fertilization (N-free fertilization) was shown in two micronutrient deficient stands in south-central Sweden. In addition, tree vitality was positively affected after the application of a site-adapted fertilizer to the canopy. Site-adaption of fertilizers will most likely improve the possibilities of a positive response on tree growth and vitality in declining stands. In a survey of Norway spruce in mixtures with beech, birch, or oak compared to monocultures it was shown that spruce nutrient status was higher in mixtures with deciduous species than in monocultures. By using mixed-species stands the need for

  1. Nutrient imbalance in Norway spruce

    Energy Technology Data Exchange (ETDEWEB)

    Thelin, Gunnar

    2000-11-01

    The studies presented in my thesis indicate that growing Norway spruce in monoculture does not constitute sustainable forest management in a high N and S deposition environment, such as in southern Sweden. The combination of N-induced high growth rates and leaching due to soil acidification causes soil reserves of nutrients to decrease. This will increase the risk of nutrient imbalance within the trees when nutrient demands are not met. The development of nutrient imbalance in Scania, southern Sweden, was shown as negative trends in needle and soil nutrient status from the mid-80s to the present in Norway spruce and Scots pine stands. This imbalance appears to be connected to high levels of N and S deposition. Clear negative effects on tree vitality were found when using a new branch development method. Today, growth and vitality seems to be limited by K, rather than N, in spruce stands older than 40 years. However, younger stands appear to be able to absorb the deposited N without negative effects on growth and vitality. When investigating effects of nutrient stress on tree vitality, indicators such as branch length and shoot multiplication rate, which include effects accumulated over several years, are suitable. Countermeasures are needed in order to maintain the forest production at a high level. Positive effects on tree nutrient status after vitality fertilization (N-free fertilization) was shown in two micronutrient deficient stands in south-central Sweden. In addition, tree vitality was positively affected after the application of a site-adapted fertilizer to the canopy. Site-adaption of fertilizers will most likely improve the possibilities of a positive response on tree growth and vitality in declining stands. In a survey of Norway spruce in mixtures with beech, birch, or oak compared to monocultures it was shown that spruce nutrient status was higher in mixtures with deciduous species than in monocultures. By using mixed-species stands the need for

  2. Impacts of absorbing aerosol deposition on snowpack and hydrologic cycle in the Rocky Mountain region based on variable-resolution CESM (VR-CESM simulations

    Directory of Open Access Journals (Sweden)

    C. Wu

    2018-01-01

    Full Text Available The deposition of light-absorbing aerosols (LAAs, such as black carbon (BC and dust, onto snow cover has been suggested to reduce the snow albedo and modulate the snowpack and consequent hydrologic cycle. In this study we use the variable-resolution Community Earth System Model (VR-CESM with a regionally refined high-resolution (0.125° grid to quantify the impacts of LAAs in snow in the Rocky Mountain region during the period 1981–2005. We first evaluate the model simulation of LAA concentrations both near the surface and in snow and then investigate the snowpack and runoff changes induced by LAAs in snow. The model simulates similar magnitudes of near-surface atmospheric dust concentrations as observations in the Rocky Mountain region. Although the model underestimates near-surface atmospheric BC concentrations, the model overestimates BC-in-snow concentrations by 35 % on average. The regional mean surface radiative effect (SRE due to LAAs in snow reaches up to 0.6–1.7 W m−2 in spring, and dust contributes to about 21–42 % of total SRE. Due to positive snow albedo feedbacks induced by the LAA SRE, snow water equivalent is reduced by 2–50 mm and snow cover fraction by 5–20 % in the two regions around the mountains (eastern Snake River Plain and southwestern Wyoming, corresponding to an increase in surface air temperature by 0.9–1.1 °C. During the snow melting period, LAAs accelerate the hydrologic cycle with monthly runoff increases of 0.15–1.00 mm day−1 in April–May and reductions of 0.04–0.18 mm day−1 in June–July in the mountainous regions. Of all the mountainous regions, the Southern Rockies experience the largest reduction of total runoff by 15 % during the later stage of snowmelt (i.e., June and July. Compared to previous studies based on field observations, our estimation of dust-induced SRE is generally 1 order of magnitude smaller in the Southern Rockies, which is ascribed to the

  3. Impacts of absorbing aerosol deposition on snowpack and hydrologic cycle in the Rocky Mountain region based on variable-resolution CESM (VR-CESM) simulations

    Science.gov (United States)

    Wu, Chenglai; Liu, Xiaohong; Lin, Zhaohui; Rahimi-Esfarjani, Stefan R.; Lu, Zheng

    2018-01-01

    The deposition of light-absorbing aerosols (LAAs), such as black carbon (BC) and dust, onto snow cover has been suggested to reduce the snow albedo and modulate the snowpack and consequent hydrologic cycle. In this study we use the variable-resolution Community Earth System Model (VR-CESM) with a regionally refined high-resolution (0.125°) grid to quantify the impacts of LAAs in snow in the Rocky Mountain region during the period 1981-2005. We first evaluate the model simulation of LAA concentrations both near the surface and in snow and then investigate the snowpack and runoff changes induced by LAAs in snow. The model simulates similar magnitudes of near-surface atmospheric dust concentrations as observations in the Rocky Mountain region. Although the model underestimates near-surface atmospheric BC concentrations, the model overestimates BC-in-snow concentrations by 35 % on average. The regional mean surface radiative effect (SRE) due to LAAs in snow reaches up to 0.6-1.7 W m-2 in spring, and dust contributes to about 21-42 % of total SRE. Due to positive snow albedo feedbacks induced by the LAA SRE, snow water equivalent is reduced by 2-50 mm and snow cover fraction by 5-20 % in the two regions around the mountains (eastern Snake River Plain and southwestern Wyoming), corresponding to an increase in surface air temperature by 0.9-1.1 °C. During the snow melting period, LAAs accelerate the hydrologic cycle with monthly runoff increases of 0.15-1.00 mm day-1 in April-May and reductions of 0.04-0.18 mm day-1 in June-July in the mountainous regions. Of all the mountainous regions, the Southern Rockies experience the largest reduction of total runoff by 15 % during the later stage of snowmelt (i.e., June and July). Compared to previous studies based on field observations, our estimation of dust-induced SRE is generally 1 order of magnitude smaller in the Southern Rockies, which is ascribed to the omission of larger dust particles (with the diameter > 10 µm) in

  4. A phase of transient subsidence, sediment bypass and deposition of regressive-transgressive cycles during the breakup of Iberia and Newfoundland

    Science.gov (United States)

    Alves, Tiago M.; Abreu Cunha, Tiago

    2018-02-01

    Seismic, outcrop and well data from West Iberia and Newfoundland are used to investigate sediment stacking patterns during continental breakup as a function of tectonic subsidence. In West Iberia, two breakup sequences are revealed on seismic data by marked strata offlap oceanwards from the present-day continental shelf. This character is similar to Newfoundland, where correlative strata comprise Lower Cretaceous-Cenomanian coarse-grained siliciclastics accumulated around local sediment-source areas. The interpreted data reveal that the two breakup sequences: 1) materialise sediment bypass onto continental-slope depocentres that experienced important tectonic subsidence during continental breakup, but without showing typical syn-rift growth packages; 2) generate specific forced-regressive stratigraphic intervals that relate to uplift and exhumation of the proximal margin. Subsidence and sediment stacking patterns in both West Iberia and Newfoundland reflect similar continental breakup processes as they evolved from the upper lithosphere- to their mantle-breakup stages. On both margins, coarse-grained siliciclastic units on the proximal margin give rise to thick shaley successions in deep-water basins. This work also confirms that in a setting dominated by a significant sediment influx, yet lacking the burial rates of continental slope basins in Newfoundland, West Iberia comprised accommodation-driven basins during continental breakup, not necessarily sediment starved. As a corollary of our analysis, we classify breakup sequences around the world based on the characteristic lithologies of their regressive-transgressive depositional cycles.

  5. Above-ground biomass and nutrient accumulation in the tropical ...

    African Journals Online (AJOL)

    This means that the impact of logging in the Ebom rainforest remains low. However, additional research is needed on nutrient input in the forest from outside as well as on the impact of logging on nutrient leaching in order to get a complete picture of the nutrient cycles. Key-words: phytomass, nutrient pools, logging, ...

  6. The subtropical nutrient spiral

    Science.gov (United States)

    Jenkins, William J.; Doney, Scott C.

    2003-12-01

    We present an extended series of observations and more comprehensive analysis of a tracer-based measure of new production in the Sargasso Sea near Bermuda using the 3He flux gauge technique. The estimated annually averaged nitrate flux of 0.84 ± 0.26 mol m-2 yr-1 constitutes only that nitrate physically transported to the euphotic zone, not nitrogen from biological sources (e.g., nitrogen fixation or zooplankton migration). We show that the flux estimate is quantitatively consistent with other observations, including decade timescale evolution of the 3H + 3He inventory in the main thermocline and export production estimates. However, we argue that the flux cannot be supplied in the long term by local diapycnal or isopycnal processes. These considerations lead us to propose a three-dimensional pathway whereby nutrients remineralized within the main thermocline are returned to the seasonally accessible layers within the subtropical gyre. We describe this mechanism, which we call "the nutrient spiral," as a sequence of steps where (1) nutrient-rich thermocline waters are entrained into the Gulf Stream, (2) enhanced diapycnal mixing moves nutrients upward onto lighter densities, (3) detrainment and enhanced isopycnal mixing injects these waters into the seasonally accessible layer of the gyre recirculation region, and (4) the nutrients become available to biota via eddy heaving and wintertime convection. The spiral is closed when nutrients are utilized, exported, and then remineralized within the thermocline. We present evidence regarding the characteristics of the spiral and discuss some implications of its operation within the biogeochemical cycle of the subtropical ocean.

  7. Soil moisture and texture primarily control the soil nutrient stoichiometry across the Tibetan grassland.

    Science.gov (United States)

    Tian, Liming; Zhao, Lin; Wu, Xiaodong; Fang, Hongbing; Zhao, Yonghua; Hu, Guojie; Yue, Guangyang; Sheng, Yu; Wu, Jichun; Chen, Ji; Wang, Zhiwei; Li, Wangping; Zou, Defu; Ping, Chien-Lu; Shang, Wen; Zhao, Yuguo; Zhang, Ganlin

    2018-05-01

    Soil nutrient stoichiometry and its environmental controllers play vital roles in understanding soil-plant interaction and nutrient cycling under a changing environment, while they remain poorly understood in alpine grassland due to lack of systematic field investigations. We examined the patterns and controls of soil nutrients stoichiometry for the top 10cm soils across the Tibetan ecosystems. Soil nutrient stoichiometry varied substantially among vegetation types. Alpine swamp meadow had larger topsoil C:N, C:P, N:P, and C:K ratios compared to the alpine meadow, alpine steppe, and alpine desert. In addition, the presence or absence of permafrost did not significantly impact soil nutrient stoichiometry in Tibetan grassland. Moreover, clay and silt contents explained approximately 32.5% of the total variation in soil C:N ratio. Climate, topography, soil properties, and vegetation combined to explain 10.3-13.2% for the stoichiometry of soil C:P, N:P, and C:K. Furthermore, soil C and N were weakly related to P and K in alpine grassland. These results indicated that the nutrient limitation in alpine ecosystem might shifts from N-limited to P-limited or K-limited due to the increase of N deposition and decrease of soil P and K contents under the changing climate conditions and weathering stages. Finally, we suggested that soil moisture and mud content could be good predictors of topsoil nutrient stoichiometry in Tibetan grassland. Copyright © 2017 Elsevier B.V. All rights reserved.

  8. Beyond the Fe-P-redox connection: preferential regeneration of phosphorus from organic matter as a key control on Baltic Sea nutrient cycles

    Directory of Open Access Journals (Sweden)

    T. Jilbert

    2011-06-01

    Full Text Available Patterns of regeneration and burial of phosphorus (P in the Baltic Sea are strongly dependent on redox conditions. Redox varies spatially along water depth gradients and temporally in response to the seasonal cycle and multidecadal hydrographic variability. Alongside the well-documented link between iron oxyhydroxide dissolution and release of P from Baltic Sea sediments, we show that preferential remineralization of P with respect to carbon (C and nitrogen (N during degradation of organic matter plays a key role in determining the surplus of bioavailable P in the water column. Preferential remineralization of P takes place both in the water column and upper sediments and its rate is shown to be redox-dependent, increasing as reducing conditions become more severe at greater water-depth in the deep basins. Existing Redfield-based biogeochemical models of the Baltic may therefore underestimate the imbalance between N and P availability for primary production, and hence the vulnerability of the Baltic to sustained eutrophication via the fixation of atmospheric N. However, burial of organic P is also shown to increase during multidecadal intervals of expanded hypoxia, due to higher net burial rates of organic matter around the margins of the deep basins. Such intervals may be characterized by basin-scale acceleration of all fluxes within the P cycle, including productivity, regeneration and burial, sustained by the relative accessibility of the water column P pool beneath a shallow halocline.

  9. Impacts of an invasive snail (Tarebia granifera) on nutrient cycling in tropical streams: the role of riparian deforestation in Trinidad, West Indies.

    Science.gov (United States)

    Moslemi, Jennifer M; Snider, Sunny B; Macneill, Keeley; Gilliam, James F; Flecker, Alexander S

    2012-01-01

    Non-native species and habitat degradation are two major catalysts of environmental change and often occur simultaneously. In freshwater systems, degradation of adjacent terrestrial vegetation may facilitate introduced species by altering resource availability. Here we examine how the presence of intact riparian cover influences the impact of an invasive herbivorous snail, Tarebia granifera, on nitrogen (N) cycling in aquatic systems on the island of Trinidad. We quantified snail biomass, growth, and N excretion in locations where riparian vegetation was present or removed to determine how snail demographics and excretion were related to the condition of the riparian zone. In three Neotropical streams, we measured snail biomass and N excretion in open and closed canopy habitats to generate estimates of mass- and area-specific N excretion rates. Snail biomass was 2 to 8 times greater and areal N excretion rates ranged from 3 to 9 times greater in open canopy habitats. Snails foraging in open canopy habitat also had access to more abundant food resources and exhibited greater growth and mass-specific N excretion rates. Estimates of ecosystem N demand indicated that snail N excretion in fully closed, partially closed, and open canopy habitats supplied 2%, 11%, and 16% of integrated ecosystem N demand, respectively. We conclude that human-mediated riparian canopy loss can generate hotspots of snail biomass, growth, and N excretion along tropical stream networks, altering the impacts of an invasive snail on the biogeochemical cycling of N.

  10. Impacts of an invasive snail (Tarebia granifera on nutrient cycling in tropical streams: the role of riparian deforestation in Trinidad, West Indies.

    Directory of Open Access Journals (Sweden)

    Jennifer M Moslemi

    Full Text Available Non-native species and habitat degradation are two major catalysts of environmental change and often occur simultaneously. In freshwater systems, degradation of adjacent terrestrial vegetation may facilitate introduced species by altering resource availability. Here we examine how the presence of intact riparian cover influences the impact of an invasive herbivorous snail, Tarebia granifera, on nitrogen (N cycling in aquatic systems on the island of Trinidad. We quantified snail biomass, growth, and N excretion in locations where riparian vegetation was present or removed to determine how snail demographics and excretion were related to the condition of the riparian zone. In three Neotropical streams, we measured snail biomass and N excretion in open and closed canopy habitats to generate estimates of mass- and area-specific N excretion rates. Snail biomass was 2 to 8 times greater and areal N excretion rates ranged from 3 to 9 times greater in open canopy habitats. Snails foraging in open canopy habitat also had access to more abundant food resources and exhibited greater growth and mass-specific N excretion rates. Estimates of ecosystem N demand indicated that snail N excretion in fully closed, partially closed, and open canopy habitats supplied 2%, 11%, and 16% of integrated ecosystem N demand, respectively. We conclude that human-mediated riparian canopy loss can generate hotspots of snail biomass, growth, and N excretion along tropical stream networks, altering the impacts of an invasive snail on the biogeochemical cycling of N.

  11. Soluble dust as source of nutrients to the global ocean and the role of humans.

    Science.gov (United States)

    Kanakidou, Maria; Myriokefalitakis, Stelios; Nikolaou, Panagiota; Daskalakis, Nikos; Theodosi, Christina; Nenes, Athanassios; Tsigaridis, Kostas; Mihalopoulos, Nikos

    2015-04-01

    Atmospheric deposition of trace constituents, both of natural and anthropogenic origin, can act as a nutrient source into the open ocean and affect marine ecosystem functioning and subsequently the exchange of CO2 between the atmosphere and the global ocean. Dust is known as a major source of nutrients (Fe and P) into the atmosphere, but only a fraction of these nutrients is released in soluble form that can be assimilated by the ecosystems. Dust is also known to enhance N deposition by interacting with anthropogenic pollutants and neutralisation of part of the acidity of the atmosphere by crustal alkaline species. The link between the soluble iron (Fe) and phosphorus (P) atmospheric deposition and atmospheric acidity, as well as anthropogenic sources, is investigated. The global atmospheric Fe, P and N cycle are parameterized in the global 3-D chemical transport model TM4-ECPL. Both primary emissions of total and soluble Fe and P associated with dust and combustion processes are taken into account, as well as inorganic and organic N emissions. The impact of atmospheric acidity on nutrient solubility is parameterised based on experimental findings. The model results are evaluated by comparison with available observations. The impact of air-quality changes on soluble nutrient deposition is studied by performing sensitivity simulations using preindustrial, present and future emission scenarios. The response of the chemical composition of nutrient-containing aerosols to environmental changes is demonstrated and quantified. This work has been supported by ARISTEIA - PANOPLY grant co-financed by European Union (ESF) and Greek national funds NSRF.

  12. Soluble dust as source of nutrients to the oceans and the role of humans

    Science.gov (United States)

    Tsigaridis, K.; Kanakidou, M.; Myriokefalitakis, S.; Nikolaou, P.; Daskalakis, N.; Theodosi, C.; Nenes, A.; Mihalopoulos, N.

    2014-12-01

    Atmospheric deposition of trace constituents, both of natural and anthropogenic origin, can act as a nutrient source into the open ocean and affect marine ecosystem functioning and subsequently the exchange of CO2 between the atmosphere and the global ocean. Dust is known as a major source of nutrients (Fe and P) into the atmosphere, but only a fraction of these nutrients is released in soluble form that can be assimilated by the ecosystems. Dust is also known to enhance N deposition by interacting with anthropogenic pollutants and neutralisation of part of the acidity of the atmosphere by crustal alkaline species. The link between the soluble iron (Fe) and phosphorus (P) atmospheric deposition and atmospheric acidity, as well as anthropogenic sources, is investigated. The global atmospheric Fe, P and N cycle are parameterized in the global 3-D chemical transport model TM4-ECPL. Both primary emissions of total and soluble Fe and P associated with dust and combustion processes are taken into account, as well as inorganic and organic N emissions. The impact of atmospheric acidity on nutrient solubility is parameterised based on experimental findings. The model results are evaluated by comparison with available observations. The impact of air-quality changes on soluble nutrient deposition is studied by performing sensitivity simulations using preindustrial, present and future emission scenarios. The response of the chemical composition of nutrient-containing aerosols to environmental changes is demonstrated and quantified. This work has been supported by ARISTEIA - PANOPLY grant co-financed by European Union (ESF) and Greek national funds NSRF.

  13. Changing Atmospheric Acidity and the Oceanic Solubility of Nutrients

    Science.gov (United States)

    Baker, Alex; Sarin, Manmohan; Duce, Robert; Jickells, Tim; Kanakidou, Maria; Myriokefalitakis, Stelios; Ito, Akinori; Turner, David; Mahowald, Natalie; Middag, Rob; Guieu, Cecile; Gao, Yuan; Croot, Peter; Shelley, Rachel; Perron, Morgane

    2017-04-01

    The atmospheric deposition of nutrients to the ocean is known to play a significant role in the marine carbon cycle. The impact of such deposition is dependent on the identity of the nutrient in question (e.g., N, P, Fe, Co, Zn, Ni, Cd), the location of the deposition, and the bioavailability of the deposited nutrient. Bioavailability is largely governed by the chemical speciation of a nutrient and, in general, insoluble species are not bioavailable. For Fe and P (and perhaps the other nutrient trace metals) solubility increases during transport through the atmosphere. The causes of this increase are complex, but interactions of aerosol particles with acids appears to play a significant role. Emissions of acidic (SO2 and NOx) and alkaline (NH3) gases have increased significantly since the Industrial Revolution, with a net increase in atmospheric acidity. This implies that Fe and P solubility may also have increased over this time period, potentially resulting in increased marine productivity. More recently, pollution controls have decreased emissions of SO2 from some regions and further reductions in SO2 and NOx are likely in the future. Emissions of NH3 are much more difficult to control however, and are projected to stabilise or increase slightly to the end of this century. Future anthropogenic emissions are thus likely to change the acidity of the atmosphere downwind of major urban / industrial centres, with potential consequences for the supply of soluble nutrients to the ocean. To address these issues UN/GESAMP Working Group 38, The Atmospheric Input of Chemicals to the Ocean, is convening a workshop on this topic at the University of East Anglia in February, 2017. The goals of this workshop are to review and synthesize the current scientific information on the solubility of aerosol-associated key biogeochemical elements, the biogeochemical controls on aerosol solubility, and the pH sensitivity of those controls; to consider the likely changes in solubility of

  14. Seasonal and Spatial Variations of Bulk Nitrogen Deposition and the Impacts on the Carbon Cycle in the Arid/Semiarid Grassland of Inner Mongolia, China.

    Directory of Open Access Journals (Sweden)

    Xianglan Li

    Full Text Available Atmospheric nitrogen (N deposition is an important component that affects the structure and function of different terrestrial ecosystem worldwide. However, much uncertainty still remains concerning the magnitude of N deposition on grassland ecosystem in China. To study the spatial and temporal patterns of bulk N deposition, the levels of N (NH4+-N and NO3--N concentration in rainfall were measured at 12 sites across a 1200 km grassland transect in Inner Mongolia, China, and the respective N deposition rates were estimated. The inorganic N deposition rates ranged from 4.53 kg N ha-1 to 12.21 kg N ha-1 with a mean value of 8.07 kg N ha-1 during the entire growing season, decreasing steadily from the eastern to the western regions. Inorganic N deposition occurred mainly in July and August across meadow steppe, typical steppe, and desert steppe, which corresponded to the seasonal distribution of mean annual precipitation. A positive relationship was found between inorganic N deposition and mean annual precipitation (R2 = 0.54 ~ 0.72, P < 0.0001 across the grassland transect. Annual estimation of inorganic N deposition was 0.67 Pg yr-1 in Inner Mongolia, China based on the correlation between N deposition rates and precipitation. N deposition was an important factor controlling aboveground biomass and ecosystem respiration, but has no effect on root biomass and soil respiration. We must clarify that we used the bulk deposition samplers during the entire sampling process and estimated the dissolved NH4+-N and NO3--N deposition rates during the entire growing season. Long-term N deposition monitoring networks should be constructed to study the patterns of N deposition and its potential effect on grassland ecosystem, considering various N species, i.e., gaseous N, particle N, and wet N deposition.

  15. Nitrogen isotopic composition of organic matter from a 168 year-old coral skeleton: Implications for coastal nutrient cycling in the Great Barrier Reef Lagoon

    Science.gov (United States)

    Erler, Dirk V.; Wang, Xingchen T.; Sigman, Daniel M.; Scheffers, Sander R.; Martínez-García, Alfredo; Haug, Gerald H.

    2016-01-01

    Ongoing human activities are known to affect nitrogen cycling on coral reefs, but the full history of anthropogenic impact is unclear due to a lack of continuous records. We have used the nitrogen isotopic composition of skeleton-bound organic matter (CS-δ15N) in a coastal Porites coral from Magnetic Island in the Great Barrier Reef as a proxy for N cycle changes over a 168 yr period (1820-1987 AD). The Magnetic Island inshore reef environment is considered to be relatively degraded by terrestrial runoff; given prior CS-δ15N studies from other regions, there was an expectation of both secular change and oscillations in CS-δ15N since European settlement of the mainland in the mid 1800s. Surprisingly, CS-δ15N varied by less than 1.5‰ despite significant land use change on the adjacent mainland over the 168-yr measurement period. After 1930, CS-δ15N may have responded to changes in local river runoff, but the effect was weak. We propose that natural buffering against riverine nitrogen load in this region between 1820 and 1987 is responsible for the observed stability in CS-δ15N. In addition to coral derived skeletal δ15N, we also report, for the first time, δ15N measurements of non-coral derived organic N occluded within the coral skeleton, which appear to record significant changes in the nature of terrestrial N inputs. In the context of previous CS-δ15N records, most of which yield CS-δ15N changes of at least 5‰, the Magnetic Island coral suggests that the inherent down-core variability of the CS-δ15N proxy is less than 2‰ for Porites.

  16. Effects of nutrient enrichment on mangrove leaf litter decomposition

    NARCIS (Netherlands)

    Keuskamp, Joost A; Hefting, Mariet M; Dingemans, Bas J J; Verhoeven, Jos T A; Feller, Ilka C

    2015-01-01

    Nutrient enrichment of mangroves, a common phenomenon along densely populated coastlines, may negatively affect mangrove ecosystems by modifying internal carbon and nutrient cycling. The decomposition of litter exerts a strong influence on these processes and is potentially modified by

  17. Associations between soil bacterial community structure and nutrient cycling functions in long-term organic farm soils following cover crop and organic fertilizer amendment.

    Science.gov (United States)

    Fernandez, Adria L; Sheaffer, Craig C; Wyse, Donald L; Staley, Christopher; Gould, Trevor J; Sadowsky, Michael J

    2016-10-01

    Agricultural management practices can produce changes in soil microbial populations whose functions are crucial to crop production and may be detectable using high-throughput sequencing of bacterial 16S rRNA. To apply sequencing-derived bacterial community structure data to on-farm decision-making will require a better understanding of the complex associations between soil microbial community structure and soil function. Here 16S rRNA sequencing was used to profile soil bacterial communities following application of cover crops and organic fertilizer treatments in certified organic field cropping systems. Amendment treatments were hairy vetch (Vicia villosa), winter rye (Secale cereale), oilseed radish (Raphanus sativus), buckwheat (Fagopyrum esculentum), beef manure, pelleted poultry manure, Sustane(®) 8-2-4, and a no-amendment control. Enzyme activities, net N mineralization, soil respiration, and soil physicochemical properties including nutrient levels, organic matter (OM) and pH were measured. Relationships between these functional and physicochemical parameters and soil bacterial community structure were assessed using multivariate methods including redundancy analysis, discriminant analysis, and Bayesian inference. Several cover crops and fertilizers affected soil functions including N-acetyl-β-d-glucosaminidase and β-glucosidase activity. Effects, however, were not consistent across locations and sampling timepoints. Correlations were observed among functional parameters and relative abundances of individual bacterial families and phyla. Bayesian analysis inferred no directional relationships between functional activities, bacterial families, and physicochemical parameters. Soil functional profiles were more strongly predicted by location than by treatment, and differences were largely explained by soil physicochemical parameters. Composition of soil bacterial communities was predictive of soil functional profiles. Differences in soil function were

  18. Process Parameters for Successful Synthesis of Carbon Nanotubes by Chemical Vapor Deposition: Implications for Chemical Mechanisms and Life-cycle Assessment

    Science.gov (United States)

    Xue, Ke

    Manufacturing of carbon nanotubes (CNTs) via chemical vapor deposition (CVD) calls for thermal treatment associated with gas-phase rearrangement and catalyst deposition to achieve high cost efficiency and limited influence on environmental impact. Taking advantage of higher degree of structure control and economical efficiency, catalytic chemical vapor deposition (CCVD) has currently become the most prevailing synthesis approach for the synthesis of large-scale pure CNTs in past years. Because the synthesis process of CNTs dominates the potential ecotoxic impacts, materials consumption, energy consumption and greenhouse gas emissions should be further limited to efficiently reduce life cycle ecotoxicity of carbon naotubes. However, efforts to reduce energy and material requirements in synthesis of CNTs by CCVD are hindered by a lack of mechanistic understanding. In this thesis, the effect of operating parameters, especially the temperature, carbon source concentration, and residence time on the synthesis were studied to improve the production efficiency in a different angle. Thus, implications on the choice of operating parameters could be provided to help the synthesis of carbon nanotubes. Here, we investigated the typical operating parameters in conditions that have yielded successful CNT production in the published academic literature of over seventy articles. The data were filtered by quality of the resultant product and deemed either "successful" or "unsuccessful" according to the authors. Furthermore, growth rate data were tabulated and used as performance metric for the process whenever possible. The data provided us an opportunity to prompt possible and common methods for practioners in the synthesis of CNTs and motivate routes to achieve energy and material minimization. The statistical analysis revealed that methane and ethylene often rely on thermal conversion process to form direct carbon precursor; further, methane and ethylene could not be the direct

  19. APORTE DE SERAPILHEIRA E NUTRIENTES EM UMA ÁREA DE CAATINGA

    Directory of Open Access Journals (Sweden)

    Alan Cauê de Holanda

    2017-01-01

    Full Text Available Caatinga is one of the Brazilian biomes where the highest degradation rates are recorded. It is associated mainly to the removal of vegetation for energy production and practice of subsistence agriculture, causing interference in nutrient cycling. The aim of the study was to quantify and chemically analyze litter deposition in a fragment of Caatinga, located in the municipality of Pombal, Paraíba (PB state. It was collected monthly for 12 months, and separated into different fractions (leaves, reproductive structures, branches and miscellaneous, all litter deposited on collectors of 1.0 m2, distributed systematically. The nutrients analyzed were N, P, K, Ca and Mg. The annual litter was of 3785.67 kg ha -1 , predominantly composed of leaf fraction with 70.2%, followed by the fraction reproductive structures with 18.3%. The nutrient content in the leaf litter followed the order Ca> N> K> Mg> P. The nutrient content in the fractions vary according to time and there is evidence of their relationship with the rainfall. The deposition of litter coincided with the seasonal period of Caatinga.

  20. Impact of biological treatments of bio-waste for nutrients, energy and bio-methane recovery in a life cycle perspective.

    Science.gov (United States)

    Di Maria, Francesco; Micale, Caterina; Contini, Stefano; Morettini, Emanuela

    2016-06-01

    Composting of the source-segregated organic fraction of municipal solid waste was compared in a life cycle perspective with conventional anaerobic digestion (AD), aimed at electricity substitution, and with AD aimed at biogas upgrading into bio-methane. Three different uses of the bio-methane were considered: injection in the natural gas grid for civil heating needs; use as fuel for high efficiency co-generation; use as fuel for vehicles. Scenarios with biogas upgrading showed quite similar impact values, generally higher than those of composting and conventional AD, for which there was a lower impact. A decisive contribution to the higher impact of the scenarios with bio-methane production was by the process for biogas upgrading. In any case the substitution of natural gas with bio-methane resulted in higher avoided impacts compared to electricity substitution by conventional AD. The uncertainty analysis confirmed the positive values for eutrophication, acidification and particulate matter. Large uncertainty was determined for global warming and photochemical ozone formation. Copyright © 2016 Elsevier Ltd. All rights reserved.

  1. Divergent taxonomic and functional responses of microbial communities to field simulation of aeolian soil erosion and deposition.

    Science.gov (United States)

    Ma, Xingyu; Zhao, Cancan; Gao, Ying; Liu, Bin; Wang, Tengxu; Yuan, Tong; Hale, Lauren; Nostrand, Joy D Van; Wan, Shiqiang; Zhou, Jizhong; Yang, Yunfeng

    2017-08-01

    Aeolian soil erosion and deposition have worldwide impacts on agriculture, air quality and public health. However, ecosystem responses to soil erosion and deposition remain largely unclear in regard to microorganisms, which are the crucial drivers of biogeochemical cycles. Using integrated metagenomics technologies, we analysed microbial communities subjected to simulated soil erosion and deposition in a semiarid grassland of Inner Mongolia, China. As expected, soil total organic carbon and plant coverage were decreased by soil erosion, and soil dissolved organic carbon (DOC) was increased by soil deposition, demonstrating that field simulation was reliable. Soil microbial communities were altered (p erosion and deposition, with dramatic increase in Cyanobacteria related to increased stability in soil aggregates. amyA genes encoding α-amylases were specifically increased (p = .01) by soil deposition and positively correlated (p = .02) to DOC, which likely explained changes in DOC. Surprisingly, most of microbial functional genes associated with carbon, nitrogen, phosphorus and potassium cycling were decreased or unaltered by both erosion and deposition, probably arising from acceleration of organic matter mineralization. These divergent responses support the necessity to include microbial components in evaluating ecological consequences. Furthermore, Mantel tests showed strong, significant correlations between soil nutrients and functional structure but not taxonomic structure, demonstrating close relevance of microbial function traits to nutrient cycling. © 2017 John Wiley & Sons Ltd.

  2. Managing urban nutrient biogeochemistry for sustainable urbanization.

    Science.gov (United States)

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

    2014-09-01

    Urban ecosystems are unique in the sense that human activities are the major drivers of biogeochemical processes. Along with the demographic movement into cities, nutrients flow towards the urban zone (nutrient urbanization), causing the degradation of environmental quality and ecosystem health. In this paper, we summarize the characteristics of nutrient cycling within the urban ecosystem compared to natural ecosystems. The dynamic process of nutrient urbanization is then explored taking Xiamen city, China, as an example to examine the influence of rapid urbanization on food sourced nitrogen and phosphorus metabolism. Subsequently, the concept of a nutrient footprint and calculation method is introduced from a lifecycle perspective. Finally, we propose three system approaches to mend the broken biogeochemical cycling. Our study will contribute to a holistic solution which achieves synergies between environmental quality and food security, by integrating technologies for nutrient recovery and waste reduction. Copyright © 2014 Elsevier Ltd. All rights reserved.

  3. Trends in nutrients

    Science.gov (United States)

    Heathwaite, A.L.; Johnes, P.J.; Peters, N.E.

    1996-01-01

    The roles of nitrogen (N) and phosphorus (P) as key nutrients determining the trophic status of water bodies are examined, and evidence reviewed for trends in concentrations of N and P species which occur in freshwaters, primarily in northern temperate environments. Data are reported for water bodies undergoing eutrophication and acidification, especially water bodies receiving increased nitrogen inputs through the atmospheric deposition of nitrogen oxides (NOx). Nutrient loading on groundwaters and surface freshwaters is assessed with respect to causes and rates of (change, relative rates of change for N and P, and implications of change for the future management of lakes, rivers and groundwaters. In particular, the nature and emphasis of studies for N species and P fractions in lakes versus rivers and groundwaters are contrasted. This review paper primarily focuses on results from North America and Europe, particularly for the UK where a wide range of data sets exists. Few nutrient loading data have been published on water bodies in less developed countries; however, some of the available data are presented to provide a global perspective. In general, N and P concentrations have increased dramatically (>20 times background concentrations) in many areas and causes vary considerably, ranging from urbanization to changes in agricultural practices.

  4. Seasonal and Spatial Variations of Bulk Nitrogen Deposition and the Impacts on the Carbon Cycle in the Arid/Semiarid Grassland of Inner Mongolia, China.

    Science.gov (United States)

    Li, Xianglan; Shi, Huiqiu; Xu, Wenfang; Liu, Wei; Wang, Xiujun; Hou, Longyu; Feng, Fei; Yuan, Wenping; Li, Linghao; Xu, Hua

    2015-01-01

    Atmospheric nitrogen (N) deposition is an important component that affects the structure and function of different terrestrial ecosystem worldwide. However, much uncertainty still remains concerning the magnitude of N deposition on grassland ecosystem in China. To study the spatial and temporal patterns of bulk N deposition, the levels of N (NH4+-N and NO3--N) concentration in rainfall were measured at 12 sites across a 1200 km grassland transect in Inner Mongolia, China, and the respective N deposition rates were estimated. The inorganic N deposition rates ranged from 4.53 kg N ha-1 to 12.21 kg N ha-1 with a mean value of 8.07 kg N ha-1 during the entire growing season, decreasing steadily from the eastern to the western regions. Inorganic N deposition occurred mainly in July and August across meadow steppe, typical steppe, and desert steppe, which corresponded to the seasonal distribution of mean annual precipitation. A positive relationship was found between inorganic N deposition and mean annual precipitation (R2 = 0.54 ~ 0.72, P ecosystem respiration, but has no effect on root biomass and soil respiration. We must clarify that we used the bulk deposition samplers during the entire sampling process and estimated the dissolved NH4+-N and NO3--N deposition rates during the entire growing season. Long-term N deposition monitoring networks should be constructed to study the patterns of N deposition and its potential effect on grassland ecosystem, considering various N species, i.e., gaseous N, particle N, and wet N deposition.

  5. What do terrestrial biogeochemistry and chemical transport models tell us about the impact of nitrogen deposition on carbon and nitrogen cycling?

    Science.gov (United States)

    Holland, E. A.; Holland, E. A.

    2001-12-01

    Evaluation of the impact of increasing nitrogen deposition on terrestrial carbon uptake requires coupling of chemical transport models and terrestrial biogeochemistry models. Simulations with a series of models and coupling schemes combined with the measurements of nitrogen deposition produce a range of results which can be used to help guide further measurements and the establishment of a appropriate networks. To help narrow uncertainties of our understanding of regional N budgets, we produced maps of N deposition fluxes from site-network observations for the US and Western Europe. These two regions of the world which have undergone profound modification of bio-atmospheric N exchanges. The maps consist of statistically interpolated fields of aqueous nitrate and ammonium, nitric acid and nitrite, and particulate nitrate and ammonium, and the interpolated spatially continuous fields allow estimation of regionally integrated budget terms. Dry deposition fluxes were the most problematic because of low station density and uncertainties associated with exchange mechanisms at the land surface. We determined dry N deposition fluxes by multiplying interpolated surface air concentrations for each chemical species by model-calculated, spatially explicit deposition velocities. Deposition of the oxidized N species, by-products of fossil fuel combustion, dominate the US N deposition budget with 2.5 Tg of NOx-N out of a total of 3.7-4.5 Tg of N deposited annually onto the conterminous US. Deposition of the reduced species, which are by-products of farming and animal husbandry, are slightly more than 50% of dominate the Western European N deposition budget with a total of 4.3-6.3 Tg of N deposited each year out of a total of 8.4-10.8 Tg N. Western Europe receives five times more N in precipitation than the conterminous US. For both regions, estimated N emissions exceed measured deposition in the US with an imbalance of 5.3-7.81. In Europe, estimated emissions better balanced

  6. Recycling nutrients in algae biorefinery

    NARCIS (Netherlands)

    Garcia Alba, Laura; Vos, M.P.; Torri, C.; Fabbri, D.; Kersten, Sascha R.A.; Brilman, Derk Willem Frederik

    2013-01-01

    Algal fuel cells: Repeated nutrient recycling is demonstrated by reusing the aqueous phase obtained from the hydrothermal liquefaction (HTL) of microalgae. This is achieved, for the first time, by performing a complete set of four continuous growth–HTL cycles. Results show similar growth rates in

  7. LITTERFALL AND NUTRIENT RETURNS IN ISOLATED STANDS ...

    African Journals Online (AJOL)

    Dr Osondu

    area has implications in returning nutrient elements to the soils of the rainforest ecosystem. Keywords: Litterfall, Nutrient returns, Seasonal variation, Southern Nigeria, Terminalia catappa, Tropical rainforest. Introduction. In the tropical rainforests, plants and soils are in equilibrium involving an almost closed cycling.

  8. Monitoring the environmental effects of CeO2 and ZnO nanoparticles through the life cycle of corn (Zea mays) plants and in situ μ-XRF mapping of nutrients in kernels.

    Science.gov (United States)

    Zhao, Lijuan; Sun, Youping; Hernandez-Viezcas, Jose A; Hong, Jie; Majumdar, Sanghamitra; Niu, Genhua; Duarte-Gardea, Maria; Peralta-Videa, Jose R; Gardea-Torresdey, Jorge L

    2015-03-03

    Information about changes in physiological and agronomic parameters through the life cycle of plants exposed to engineered nanoparticles (NPs) is scarce. In this study, corn (Zea mays) plants were cultivated to full maturity in soil amended with either nCeO2 or nZnO at 0, 400, and 800 mg/kg. Gas exchange was monitored every 10 days, and at harvest, bioaccumulation of Ce and Zn in tissues was determined by ICP-OES/MS. The effects of NPs exposure on nutrient concentration and distribution in ears were also evaluated by ICP-OES and μ-XRF. Results showed that nCeO2 at both concentrations did not impact gas exchange in leaves at any growth stage, while nZnO at 800 mg/kg reduced net photosynthesis by 12%, stomatal conductance by 15%, and relative chlorophyll content by 10% at day 20. Yield was reduced by 38% with nCeO2 and by 49% with nZnO. Importantly, μ-XRF mapping showed that nCeO2 changed the allocation of calcium in kernels, compared to controls. In nCeO2 treated plants, Cu, K, Mn, and Zn were mainly localized at the insertion of kernels into cobs, but Ca and Fe were distributed in other parts of the kernels. Results showed that nCeO2 and nZnO reduced corn yield and altered quality of corn.

  9. A 3D parameterization of iron atmospheric deposition to the global ocean

    Science.gov (United States)

    Myriokefalitakis, Stelios; Krol, Maarten C.; van Noije, Twan P. C.; Le Sager, Philippe

    2017-04-01

    Atmospheric deposition of trace constituents, both of natural and anthropogenic origin, can act as a nutrient source into the open ocean and affect marine ecosystem functioning and subsequently the exchange of CO2 between the atmosphere and the global ocean. Dust is known as a major source of nutrients to the global ocean, but only a fraction of these nutrients is released in soluble form that can be assimilated by the ecosystems. Iron (Fe) is a key micronutrient that significantly modulates gross primary production in High-Nutrient-Low-Chlorophyll (HNLC) oceans, where macronutrients like nitrate are abundant but primary production is limited by Fe scarcity. The global atmospheric Fe cycle is here parameterized in the state-of-the-art global Earth System Model EC-Earth. The model takes into account the primary emissions of both insoluble and soluble Fe, associated with dusts and combustion processes. The impact of atmospheric acidity on mineral solubility is parameterized based on updated experimental and theoretical findings, and model results are evaluated against available observations. The link between the soluble Fe atmospheric deposition and anthropogenic sources is also investigated. Overall, the response of the chemical composition of nutrient containing aerosols to atmospheric composition changes is demonstrated and quantified. This work has been financed by the Marie-Curie H2020-MSCA-IF-2015 grant (ID 705652) ODEON (Online DEposition over OceaNs: Modeling the effect of air pollution on ocean bio-geochemistry in an Earth System Model).

  10. Ovoviviparity in platyhelminth life-cycles.

    Science.gov (United States)

    Tinsley, R C

    1983-04-01

    The encapsulated embryos of platyhelminths may be retained and complete their development in utero in a range of circumstances. However, hatching within the parent (the criterion of ovoviviparity) is relatively rare and larvae generally emerge only after deposition. Viviparity is characterized by the nutritional dependency of the unencapsulated larva upon the parent, but in several cases larvae retained within a shell also receive parental nutrients during intra-uterine development. Uptake of exogenous nutrients via shell pores occurs in Schistosoma mansoni but the eggs, which gain all the advantages of intra-uterine retention, are supported by host nutrients. Intra-uterine larval development avoids the hazards of development in the external environment and eliminates the time delay between oviposition and infection. Deposition of immediately infective offspring may be concentrated in time and space to exploit periods of host vulnerability. The control and precision of transmission is illustrated by examples in which the opportunity for invasion is restricted because of either host behaviour or environmental instability. This strategy has been an important factor in the evolution of polystomatid monogeneans, and its effectiveness is demonstrated by comparison of the life-cycles of Polystoma integerrimum and Pseudodiplorchis americanus. Ovoviviparity also increases reproductive potential in some polystomatids by extending the period of multiplication and by increasing established populations through internal re-infection. In Eupolystoma alluaudi, the capacity for ovoviviparity is programmed into larval development and this regulates population growth within individual hosts.

  11. Adubação nitrogenada na aveia preta. I - Influência na produção de matéria seca e ciclagem de nutrientes sob sistema plantio direto Black oat biomass and nutrient cycling as affected by nitrogen fertilization in soil under no-tillage

    Directory of Open Access Journals (Sweden)

    A. Santi

    2003-12-01

    % higher than in oat without N application. At the estimated N application rate of 120 kg ha-1, the amount of recycled Ca increased by 95 % and the recycled Mg by 90 %, compared to the treatment without nitrogen fertilizer. The C/N ratio of the produced residues decreased by about one unit for each 10 kg ha-1 of applied N. In conclusion, N fertilization is a viable alternative to increase the quality and quantity of black oat biomass added to soils in no-tillage systems; besides, it improves nutrient cycling.

  12. Incorporating hydrologic variability into nutrient spiraling

    Science.gov (United States)

    Doyle, Martin W.

    2005-09-01

    Nutrient spiraling describes the path of a nutrient molecule within a stream ecosystem, combining the biochemical cycling processes with the downstream driving force of stream discharge. To date, nutrient spiraling approaches have been hampered by their inability to deal with fluctuating flows, as most studies have characterized nutrient retention within only a small range of discharges near base flow. Here hydrologic variability is incorporated into nutrient spiraling theory by drawing on the fluvial geomorphic concept of effective discharge. The effective discharge for nutrient retention is proposed to be that discharge which, over long periods of time, is responsible for the greatest portion of nutrient retention. A developed analytical model predicts that the effective discharge for nutrient retention will equal the modal discharge for small streams or those with little discharge variability. As modal discharge increases or discharge variability increases, the effective discharge becomes increasingly less than the modal discharge. In addition to the effective discharge, a new metric is proposed, the functionally equivalent discharge, which is the single discharge that will reproduce the magnitude of nutrient retention generated by the full hydrologic frequency distribution when all discharge takes place at that rate. The functionally equivalent discharge was found to be the same as the modal discharge at low hydrologic variability, but increasingly different from the modal discharge at large hydrologic variability. The functionally equivalent discharge provides a simple quantitative means of incorporating hydrologic variability into long-term nutrient budgets.

  13. Evidence for Subglacial Deformation and Deposition during a Complete Advance-Stagnation Cycle of Kötlujökull, Iceland – A Case Study

    DEFF Research Database (Denmark)

    Klint, K E S; Richardt, N; Krüger, Johannes

    2010-01-01

    A geological section, 70 m long and 3–4 m high, cut into dead-ice moraine in front of Kötlujökull, has been described. Five-sediment associations were recognized representing (1) proglacial glacio-fluvial sedimentation, (2) deposition and deformation in ice-marginal environment, (3) subglacial...

  14. Dating by thermoluminescence of some costal sand deposits of last climatic cycle, from the northeastern region of Rio Grande do Sul State, Brazil

    International Nuclear Information System (INIS)

    Poupeau, G.; Rivera, A.

    1988-01-01

    Six coastal quartz sand deposits from the northeastern region of the Rio Grande do Sul State (Brazil), with reasonnably well known ages, from ∼ 1700 yr to ∼ 120.000 yr, were dated by thermoluminescence. (M.W.O.) [pt

  15. Area-Selective Atomic Layer Deposition of SiO2 Using Acetylacetone as a Chemoselective Inhibitor in an ABC-Type Cycle

    NARCIS (Netherlands)

    Mameli, A.; Merkx, M.J.M.; Karasulu, B.; Roozeboom, F.; Kessels, W.E.M.M.; MacKus, A.J.M.

    2017-01-01

    Area-selective atomic layer deposition (ALD) is rapidly gaining interest because of its potential application in self-aligned fabrication schemes for next-generation nanoelectronics. Here, we introduce an approach for area-selective ALD that relies on the use of chemoselective inhibitor molecules in

  16. Nitrogen cycling in ombrotrophic peat bogs in the Czech Republic: Is microbial N-fixation occurring at atmospheric depositions of reactive N higher than 10 kg/ha/yr?

    Science.gov (United States)

    Novak, Martin; Jackova, Ivana; Cejkova, Bohuslava; Buzek, Frantisek; Curik, Jan; Stepanova, Marketa; Prechova, Eva; Veselovsky, Frantisek; Komarek, Arnost

    2017-04-01

    Biogeochemical cycling of carbon (C) and nitrogen (N) in peat bogs are coupled. Whereas at low pollution levels, reactive nitrogen (Nr, mainly nitrate- and ammonium-N) inputs may positively affect C storage, high Nr deposition may have a detrimental effect on C storage. We have previously reported N isotope systematics at two ombrotrophic peat bogs in the Czech Republic, receiving medium levels of Nr of about 10 kg/ha/yr via atmospheric deposition. Nitrogen of living Sphagnum was systematically heavier than N of the atmospheric input (p water prior to the 15N-N2 incubation has led to a slight further increase in del15N of Sphagnum. Also in 2016, we monitored del15N of atmospheric deposition at three medium Nr-polluted peat bogs. Open-area precipitation had the following mean del 15N values: Uhlirska -6.1 per mil (NH4) and -6.2 per mil (NO3); Brumiste -1.7 per mil (NH4) and -3.4 per mil (NO3); Male Mechove Jezirko -3.3 per mil (NH4) and -3.9 per mil (NO3). At all sites, atmospheric Nr deposition was made up by NO3-N and NH4-N in a roughly 1.1 ratio. We found that N of winter-time deposition became isotopically extremely light (less than -10.0 per mil). During the growing season, del15N of total atmospheric input was higher, closer to 0.0 per mil, but still slightly lower than del15N of living Sphagnum. These data thus confirm a N isotope discrepancy between the N isotope signature of deposition and Sphagnum. In the paper, we will also discuss a mass balance discrepancy in long-term atmospheric N input and N storage at the Czech sites, determined for replicated, lead-210 dated peat cores. We took into consideration a 30 % contribution of horizontal deposition (mainly fog interception), which we had directly measured, to total Nr deposition. Still, the dated peat cores appeared to accumulate 30 to 60 % more N than the maximum estimated atmospheric Nr input (both estimates for the period 1900-2015). Preliminarily, we conclude that three independent lines of evidence

  17. Depositional Cycles on Magmatic and Back Arcs: an Example from Western Lndonesla Cycles sédimentaires dans les arcs magmatiques et les bassins d'arrière arcs. Un exemple : l'Indonésie occidentale

    Directory of Open Access Journals (Sweden)

    Baumann P.

    2006-11-01

    Full Text Available Cainozoic sedimentation cycles are described from the magmatic arc occupied by the islands of Sumatra and Java and of its backarc area, the Sundashelf. Four sedimentation cycles can be individualized on Sumatra and Java (Fig. 9, each starting with a transgression and terminating with a phase of volcanism and tectonism. The transgression that initiated an additional cycle is known from Northeast Sumatra but its pertinent volcanic end phase if present could not yet be recognized. The succession of sediments of the four complete cycles show a causal related stratigraphic order. They can be regarded as lithotectonic units and are shown to have been caused by geotectonic events. Acceleration of spreading first caused the transgression (Pitman 1978 that initiated the cycle. lt subsequently increased the rate of subduction what in turn produced an increase of tectonic stress and volcanism on the active plate margin. Plusieurs cycles sédimentaires du Cénozoïque appartenant à l'arc magmatique, constitué par les îles de Java et Sumatra et à son arrière-arc , et au plateau continental de la Sonde, sont décrits et discutés. Quatre cycles sédimentaires peuvent être reconnus à Java et Sumatra (f ig. 9, commençant chacun par une transgression et se terminant par une phase volcanique et tectonique. Dans le nord-est de Sumatra, une transgression appartenant à un cinquième cycle a été reconnue : cependant la phase terminale volcanique de ce cycle, si elle n'a jamais existé, n'a pas encore pu être mise en évidence. Le dépôt des couches appartenant aux quatre cycles complets a eu lieu en respectant un ordre stratigraphique bien déterminé. On peut considérer ce dépôt de couches sédimentaires, comme une unité lithotectonique déposée à la faveur des mécanismes géotectoniques. La transgression initiale de chaque cycle a été provoquée par une accélération de l'expansion océanique (Pitman 1978. Cette accélération, par ailleurs

  18. Reducing Abdominal Fat Deposition in Broiler Through Feeding Management

    Directory of Open Access Journals (Sweden)

    Cecep Hidayat

    2015-09-01

    Full Text Available Abdominal fat in broiler carcass is considered as a waste and its existence reduces the carcass quality. Abdominal fat deposition is affected by several factors such as genetic, nutrition, feed, sex, age and environment. Reducing abdominal fat deposition can be carried out by regulating the nutrient intake to ensure that no excessive nutrient was consumed. Nutrition effects to reduce abdominal fat deposition are associated with nutrient concentration of ration and quantity of daily feed intake. Daily nutrient intake can be limited, especially through restricted feeding. It is concluded that an appropriate feeding management can reduce abdominal fat deposition in broiler.

  19. Modeling the element cycle of aquatic plants

    International Nuclear Information System (INIS)

    Asaeda, Takashi

    2007-01-01

    Aquatic plants play an important role in element cycles in wetlands and the efficiency of the process is extremely related to their proportional biomass allocation to above- and belowground organs. Therefore, the framework of most macrophyte productivity models is usually similar with a mass-balance approach consisting of gross production, respiration and mortality losses and the translocation between organs. These growth models are incorporated with decomposition models to evaluate the annual cycle of elements. Perennial emergent macrophytes with a relatively large biomass have a particularly important role in element cycles. Their phenological stages, such as the beginning of hibernation of belowground rhizome systems, emergence of new shoots in spring with resources stocked in the rhizomes, flowering, downward translocation of photosynthetic products later on and then the mortality of the aboveground system in late autumn, depend on the environmental conditions, basically the nutrients, water depth, climatic variations, etc. Although some species retain standing dead shoots for a long time, dead shoots easily fall into water, starting to decompose in the immediate aftermath. However, their decomposition rates in the water are relatively low, causing to accumulate large amounts of organic sediments on the bottom. Together with the deposition of allochthonous suspended matters in the stand, this process decreases the water depth, transforming wetlands gradually into land. The depth of penetration of roots into the sediments to uptake nutrients and water is extremely site specific, however, in water-logged areas, the maximum penetrable depth may be approximately estimated by considering the ability of oxygen transport into the rhizome system. The growth of perennial submerged plants is also estimated by a process similar to that of emergent macrophytes. However, compared with emergent macrophytes, the root system of submerged macrophytes is weaker, and the nutrient

  20. Predator control of ecosystem nutrient dynamics.

    Science.gov (United States)

    Schmitz, Oswald J; Hawlena, Dror; Trussell, Geoffrey C

    2010-10-01

    Predators are predominantly valued for their ability to control prey, as indicators of high levels of biodiversity and as tourism attractions. This view, however, is incomplete because it does not acknowledge that predators may play a significant role in the delivery of critical life-support services such as ecosystem nutrient cycling. New research is beginning to show that predator effects on nutrient cycling are ubiquitous. These effects emerge from direct nutrient excretion, egestion or translocation within and across ecosystem boundaries after prey consumption, and from indirect effects mediated by predator interactions with prey. Depending on their behavioural ecology, predators can create heterogeneous or homogeneous nutrient distributions across natural landscapes. Because predator species are disproportionately vulnerable to elimination from ecosystems, we stand to lose much more from their disappearance than their simple charismatic attractiveness. 2010 Blackwell Publishing Ltd/CNRS.

  1. Interactions among hydrogeomorphology, vegetation, and nutrient biogeochemistry in floodplain ecosystems

    Science.gov (United States)

    Noe, G.B.

    2013-01-01

    Hydrogeomorphic, vegetative, and biogeochemical processes interact in floodplains resulting in great complexity that provides opportunities to better understand linkages among physical and biological processes in ecosystems. Floodplains and their associated river systems are structured by four dimensional gradients of hydrogeomorphology: longitudinal, lateral, vertical, and temporal components. These four dimensions create dynamic hydrologic and geomorphologic mosaics that have a large imprint on the vegetation and nutrient biogeochemistry of floodplains. Plant physiology, population dynamics, community structure, and productivity are all very responsive to floodplain hydrogeomorphology. The strength of this relationship between vegetation and hydrogeomorphology is evident in the use of vegetation as an indicator of hydrogeomorphic processes. However, vegetation also influences hydrogeomorphology by modifying hydraulics and sediment entrainment and deposition that typically stabilize geomorphic patterns. Nitrogen and phosphorus biogeochemistry commonly influence plant productivity and community composition, although productivity is not limited by nutrient availability in all floodplains. Conversely, vegetation influences nutrient biogeochemistry through direct uptake and storage as well as production of organic matter that regulates microbial biogeochemical processes. The biogeochemistries of nitrogen and phosphorus cycling are very sensitive to spatial and temporal variation in hydrogeomorphology, in particular floodplain wetness and sedimentation. The least studied interaction is the direct effect of biogeochemistry on hydrogeomorphology, but the control of nutrient availability over organic matter decomposition and thus soil permeability and elevation is likely important. Biogeochemistry also has the more documented but indirect control of hydrogeomorphology through regulation of plant biomass. In summary, the defining characteristics of floodplain ecosystems

  2. Long- and short-term changes in nutrient availability following commercial sawlog harvest via cable logging

    Science.gov (United States)

    Jennifer Knoepp; Wayne Swank; Bruce L. Haines

    2014-01-01

    Soil nutrient availability often limits forest productivity and soils have considerable variation in their ability to supply nutrients. Most southern Appalachian forests are minimally managed with no fertilizer inputs or routine thinning regime. Nutrient availability is regulated by atmospheric inputs and the internal cycling of nutrients through such processes as...

  3. An experimental study on the characteristics and delamination of TiN coatings deposited on Al 7075-T6 under fatigue cycling

    International Nuclear Information System (INIS)

    Oskouei, R.H.; Ibrahim, R.N.; Barati, M.R.

    2012-01-01

    In this paper, delamination of a titanium nitride (TiN) thin film from an aluminium alloy 7075-T6 substrate has been studied under fatigue loading conditions. TiN coatings of 3 μm in thickness were deposited onto the aluminium substrate using a physical vapour deposition process. Fatigue fracture surfaces of the coated specimens, failed under a range of low to high cyclic loads, were examined by means of scanning electron microscopy (SEM). SEM analyses showed that the coating layer remained well-adhered to the substrate under fatigue loading with maximum stresses less than 200 MPa. However, local delaminations were observed at maximum cyclic stresses higher than 200 MPa. The coated specimens were found to beneficially resist maximum cyclic stresses up to 350 MPa without showing delaminations when subjected to a modified post heat treatment with a high solutionising temperature. This was associated with an average improvement of 27% in the fatigue life of the coated specimens subjected to the post heat treatment in a controlled atmosphere (argon) when compared to uncoated Al 7075-T6 for tested maximum alternating stress levels. Characterisation of TiN coatings confirmed the presence of single phase TiN film onto the substrate without any oxidisation when heat treated in argon atmosphere. Moreover, compressive residual stresses in TiN coatings increased from − 4.54 to − 7.56 GPa after the post heat treatment as a result of thermal stresses introduced during the quenching stage of the heat treatment. The actual lattice parameters were determined using the Cohen–Wagner method and were found to increase from 4.257 (Å) for the as-deposited TiN coatings to 4.262 (Å) for TiN coatings subjected to the post heat treatment. - Highlights: ► Improvement in fatigue life of TiN coated Al 7075-T6 after a post heat treatment ► Excellent adhesion of TiN film to the substrate at low and moderate cyclic loads ► Local delaminations of TiN film from Al 7075-T6 substrate

  4. Anthropogenic Nutrient Loading in the Northeastern US 1920-2000

    Science.gov (United States)

    Hale, R. L.; Ng, M.; Brideau, J. M.; Hoover, J. H.; Thomas, B.

    2010-12-01

    Human activities have dramatically altered biogeochemical cycles on local to global scales. Altered fluxes of nutrients (nitrogen, phosphorus) to freshwater systems have been driven directly by human-mediated fluxes (e.g., industrial N fixation) and indirectly due to changes in land and water systems that alter rates of biogeochemical transformations and transport vectors for nutrients. The Northeastern United States as a region underwent many biophysical and political changes over the 20th century, making it an excellent case study for understanding human-biogeochemical relationships over time. From 1920 to 2000, this region experienced significant losses of agricultural land and increases in forest and urban land cover. Furthermore, major national and state legislation, including nuisance laws and the Clean Water Act, was passed during the 20th century to control pollution problems, and major technological advances in wastewater treatment were made. Our goals were to: 1) describe quantitative changes in the spatial patterns of water quality over time, 2) understand the proximate (e.g., changes in land use, new technology) and 3) ultimate (e.g., major demographic, economic, social shifts) drivers of those patterns. Using data from the historic Census of Agriculture, the National Atmospheric Deposition Program, and primary literature, we create a comprehensive time series database of anthropogenic N and P inputs to the Northeast terrestrial system. Inputs are estimated for each county at decadal time scales. Inputs included atmospheric deposition of nitrogen, fertilizer, manure, enhanced biological nitrogen fixation, and domestic waste. We used this database, in conjunction with data on land use, reservoirs, climate, and stream nutrient loads estimated from USGS NWIS to develop a modified export coefficient model for 26 watersheds in the Northeast. We then used this model to estimate nutrient loads at the decadal scale for all HUC 8 watersheds in our study region

  5. Crop yield, root growth, and nutrient dynamics in a conventional and three organic cropping systems with different levels of external inputs and N re-cycling through fertility building crops

    DEFF Research Database (Denmark)

    Thorup-Kristensen, Kristian; Dresbøll, Dorte Bodin; Kristensen, Hanne Lakkenborg

    2012-01-01

    of the organic rotation, both relying on green manures and catch crops grown during the autumn after the main crop as their main source of soil fertility, and the O3 system further leaving rows of the green manures to grow as intercrops between vegetable rows to improve the conditions for biodiversity...... calculated based on total land area was only 63% of conventional yields. Differences in quality parameters of the harvested crops, i.e. nutrient content, dry matter content or damages by pests or diseases were few and not systematic, whereas clear effects on nutrient balances and nitrogen leaching indicators...

  6. Soluble organic nutrient fluxes

    Science.gov (United States)

    Robert G. Qualls; Bruce L. Haines; Wayne Swank

    2014-01-01

    Our objectives in this study were (i) compare fluxes of the dissolved organic nutrients dissolved organic carbon (DOC), DON, and dissolved organic phosphorus (DOP) in a clearcut area and an adjacent mature reference area. (ii) determine whether concentrations of dissolved organic nutrients or inorganic nutrients were greater in clearcut areas than in reference areas,...

  7. Plant nutrient capacity of vineyard soils at Grimalda area of central Istria

    OpenAIRE

    Matković, D.; Gluhič, David

    2016-01-01

    During annual grow cycle the vines develop forms of vegetative and generative organs. For this it needs plant nutrients in the soil, which are located in the root zone. Plant nutrients are substances which are necessary for the life cycle of the plant. Each nutrient element has its own specific physiological role in plant metabolism. With the highly complex functions of roots, vines take mineral nutrients from the soil, which are dissolved in water. For the successful cultivation of vines is ...

  8. Acid deposition and water use efficiency in Appalachian forests

    Science.gov (United States)

    Malcomb, J.

    2017-12-01

    Multiple studies have reported increases in forest water use efficiency in recent decades, but the drivers of these trends remain uncertain. While acid deposition has profoundly altered the biogeochemistry of Appalachian forests in the past century, its impacts on forest water use efficiency have been largely overlooked. Plant ecophysiology literature suggests that plants up-regulate transpiration in response to soil nutrient limitation in order to maintain sufficient mass flow of nutrients. To test the impacts of acid deposition on forest eco-hydrology in central Appalachia, we integrated dendrochronological techniques, including tree ring δ13C analysis, with catchment water balance data from the Fernow Experimental Forest in West Virginia. Tree cores from four species were collected in Fernow Watershed 3, which has received experimental ammonium sulfate additions since 1989, and Watershed 7, an adjacent control catchment. Initial results suggest that acidification treatments have not significantly influenced tree productivity compared to a control watershed, but the effect varies by species, with tulip poplar showing greatest sensitivity to acidification. Climatic water balance, defined as the difference between growing season precipitation and evapotranspiration, is significantly related to annual tree ring growth, suggesting that climate may be driving tree growth trends in chronically acidified Appalachian forests. Tree ring 13C analysis from Fernow cores is underway and these data will be integrated with catchment hydrology data from five other sites in central Appalachia and the U.S. Northeast, representing a range of forest types, soil base saturations, and acid deposition histories. This work will advance understanding of how climate and acid deposition interact to influence forest productivity and water use efficiency, and improve our ability to model carbon and water cycling in forested ecosystems impacted by acid deposition.

  9. Seasonal changes in hepatocytic lipid droplets, glycogen deposits, and rough endoplasmic reticulum along the natural breeding cycle of female ohrid trout (Salmo letnica Kar.)-A semiquantitative ultrastructural study.

    Science.gov (United States)

    Jordanova, Maja; Rebok, Katerina; Malhão, Fernanda; Rocha, Maria J; Rocha, Eduardo

    2016-08-01

    This study on wild female Ohrid trout was primarily designed to provide a general overview of the breeding cycle influence upon selected aspects of hepatocytes. According with a semiquantitatively evaluation, some of these cell's structural compartments change during the breeding cycle. Structural modifications were disclosed in the relative occurrence of lipid, glycogen, and RER content during breeding cycle. The relative amount of lipid deposits in the hepatocytes was much greater in previtellogenesis, and decreased postspawning. So, while the seasonal changes in RER were positively related with the ovary maturation status, those of the lipid droplets followed an opposite trend. The hepatocytic glycogen occurred rarely, mainly in late-vitellogenesis and spawning, suggesting that in this species such kind of energy storage is comparatively unimportant. Lipid accumulation and later usage is, probably, the relevant biochemical pathway for Ohrid trout in the wild. While glycogen and RER contents were positively correlated with the gonadosomatic index, lipids were negatively correlated. Additionally, glycogen inclusions were positively correlated with the plasma estradiol levels. When comparing seasonal patterns from wild Ohrid trout with those from well-studied rainbow and brown trout (specimens studied were from aquaculture), there are contradicting results as to lipid and glycogen reserves, and also as to RER loads. The differences among the mentioned trout can result from intrinsic interspecies differences or may be associated with natural feeding conditions versus feeding with commercially prepared diets, or other factors. This study offers new data useful as standard to access liver pathology in wild and aquacultured Ohrid trout. Microsc. Res. Tech. 79:700-706, 2016. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

  10. Nutrient fluxes in rainfall, throughfall and stemflow in Eucalyptus ...

    African Journals Online (AJOL)

    This study adds value to understanding of nutritional sustainability of fast-growing plantation forests, demonstrating the importance of atmospheric deposition as a nutrient addition source to plantation-grown eucalypts along the Zululand coastal plain. Keywords: atmospheric deposition, canopy exchange, clonal Eucalyptus, ...

  11. Patchiness in a minimal nutrient – phytoplankton model

    Indian Academy of Sciences (India)

    Srinivas

    increase in nutrient loading, which means the progress of eutrophication, makes the system converge to a stable equilibrium state. The return to homogeneous distribution means that adoption of the two-component model with nutrients and phytoplankton is one of the possible ways to avoid continuing limit-cycle oscillations ...

  12. Nutrient use efficiency in the food chain of China

    NARCIS (Netherlands)

    Ma, L.

    2014-01-01

      Key words: Nitrogen, phosphorus, food chain, food pyramid, food system, food security, food cost, environmental impacts, nutrient cycling, nutrient management

    Nitrogen (N) and phosphorus (P) fertilizer applications have greatly contributed to the increased

  13. Nutrient Acquisition and the Metabolic Potential of Photoferrotrophic Chlorobi

    Directory of Open Access Journals (Sweden)

    Katharine J. Thompson

    2017-07-01

    Full Text Available Anoxygenic photosynthesis evolved prior to oxygenic photosynthesis and harnessed energy from sunlight to support biomass production on the early Earth. Models that consider the availability of electron donors predict that anoxygenic photosynthesis using Fe(II, known as photoferrotrophy, would have supported most global primary production before the proliferation of oxygenic phototrophs at approximately 2.3 billion years ago. These photoferrotrophs have also been implicated in the deposition of banded iron formations, the world’s largest sedimentary iron ore deposits that formed mostly in late Archean and early Proterozoic Eons. In this work we present new data and analyses that illuminate the metabolic capacity of photoferrotrophy in the phylum Chlorobi. Our laboratory growth experiments and biochemical analyses demonstrate that photoferrotrophic Chlorobi are capable of assimilatory sulfate reduction and nitrogen fixation under sulfate and nitrogen limiting conditions, respectively. Furthermore, the evolutionary histories of key enzymes in both sulfur (CysH and CysD and nitrogen fixation (NifDKH pathways are convoluted; protein phylogenies, however, suggest that early Chlorobi could have had the capacity to assimilate sulfur and fix nitrogen. We argue, then, that the capacity for photoferrotrophic Chlorobi to acquire these key nutrients enabled them to support primary production and underpin global biogeochemical cycles in the Precambrian.

  14. Element cycling in forest soils - modelling the effects of a changing environment

    Energy Technology Data Exchange (ETDEWEB)

    Walse, C.

    1998-11-01

    Element cycling and nutrient supply in forest ecosystems are of vital importance for short-term productivity and for longer-term land management in terms of nutrient leaching and CO{sub 2} fixation. This thesis includes a series of studies with the objective of modelling some aspects of the effect of acidification and climate change on element cycling and nutrient supply in forest soil. A reconstruction model of atmospheric deposition and nutrient uptake and cycling, MAKEDEP, was developed. An existing model of soil chemistry, SAFE, was analyzed and applied. SAFE+MAKEDEP were then applied in combination with the RAINS model to perform scenario analyses of soil acidification/recovery for six European forest sites. A decomposition model intended to run in conjunction with the SAFE model was developed. Key elements were N, Ca, K, Mg, S and Al. In the decomposition model, only carbon release was included to date.The results show, that understanding the history of soil geochemistry is important for modelling the system and for projecting the future impact of acidification on nutrient supply in forest soils. The applied reconstruction models of acid deposition (MAKEDEP, RAINS) seem to generate reasonable and consistent estimates of historic acid deposition, so that present day conditions can be simulated starting from pre-acidification conditions. From applications of the SAFE model to large-scale forest manipulation experiments, we conclude that the geochemical processes and the degree of detail in process descriptions included in SAFE are adequate to capture the most important aspects of soil solution dynamics of forest soils in northern and central Europe. Therefore, SAFE is appropriate for the simulation of acidification and recovery scenarios for these soils. The precision in model prediction on a more general scale is often limited by factors other than model formulation, such as consistency and representativity of input data. It is shown that the physical

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

    Science.gov (United States)

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

    2013-01-01

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

  16. Response of dissolved carbon and nitrogen concentrations to moderate nutrient additions in a tropical montane forest of south Ecuador

    Directory of Open Access Journals (Sweden)

    Andre eVelescu

    2016-05-01

    Full Text Available In the past two decades, the tropical montane rain forests in south Ecuador experienced increasing deposition of reactive nitrogen mainly originating from Amazonian forest fires, while Saharan dust inputs episodically increased deposition of base metals. Increasing air temperature and unevenly distributed rainfall have allowed for longer dry spells in a perhumid ecosystem. This might have favored mineralization of dissolved organic matter (DOM by microorganisms and increased nutrient release from the organic layer. Environmental change is expected to impact the functioning of this ecosystem belonging to the biodiversity hotspots of the Earth.In 2007, we established a nutrient manipulation experiment (NUMEX to understand the response of the ecosystem to moderately increased nutrient inputs. Since 2008, we have continuously applied 50 kg ha-1 a-1 of nitrogen (N, 10 kg ha-1 a-1 of phosphorus (P, 50 kg + 10 kg ha-1 a-1 of N and P and 10 kg ha-1 a-1 of calcium (Ca in a randomized block design at 2000 m a.s.l. in a natural forest on the Amazonia-exposed slopes of the south Ecuadorian Andes.Nitrogen concentrations in throughfall increased following N+P additions, while separate N amendments only increased nitrate concentrations. Total organic carbon (TOC and dissolved organic nitrogen (DON concentrations showed high seasonal variations in litter leachate and decreased significantly in the P and N+P treatments, but not in the N treatment. Thus, P availability plays a key role in the mineralization of DOM. TOC/DON ratios were narrower in throughfall than in litter leachate but their temporal course did not respond to nutrient amendments.Our results revealed an initially fast, positive response of the C and N cycling to nutrient additions which declined with time. TOC and DON cycling only change if N and P supply are improved concurrently, while NO3-N leaching increases only if N is separately added. This indicates co-limitation of the microorganisms by N

  17. Response of dissolved carbon and nitrogen concentrations to moderate nutrient additions in a tropical montane forest of south Ecuador

    Science.gov (United States)

    Velescu, Andre; Valarezo, Carlos; Wilcke, Wolfgang

    2016-05-01

    In the past two decades, the tropical montane rain forests in south Ecuador experienced increasing deposition of reactive nitrogen mainly originating from Amazonian forest fires, while Saharan dust inputs episodically increased deposition of base metals. Increasing air temperature and unevenly distributed rainfall have allowed for longer dry spells in a perhumid ecosystem. This might have favored mineralization of dissolved organic matter (DOM) by microorganisms and increased nutrient release from the organic layer. Environmental change is expected to impact the functioning of this ecosystem belonging to the biodiversity hotspots of the Earth. In 2007, we established a nutrient manipulation experiment (NUMEX) to understand the response of the ecosystem to moderately increased nutrient inputs. Since 2008, we have continuously applied 50 kg ha-1 a-1 of nitrogen (N), 10 kg ha-1 a-1 of phosphorus (P), 50 kg + 10 kg ha-1 a-1 of N and P and 10 kg ha-1 a-1 of calcium (Ca) in a randomized block design at 2000 m a.s.l. in a natural forest on the Amazonia-exposed slopes of the south Ecuadorian Andes. Nitrogen concentrations in throughfall increased following N+P additions, while separate N amendments only increased nitrate concentrations. Total organic carbon (TOC) and dissolved organic nitrogen (DON) concentrations showed high seasonal variations in litter leachate and decreased significantly in the P and N+P treatments, but not in the N treatment. Thus, P availability plays a key role in the mineralization of DOM. TOC/DON ratios were narrower in throughfall than in litter leachate but their temporal course did not respond to nutrient amendments. Our results revealed an initially fast, positive response of the C and N cycling to nutrient additions which declined with time. TOC and DON cycling only change if N and P supply are improved concurrently, while NO3-N leaching increases only if N is separately added. This indicates co-limitation of the microorganisms by N and P

  18. Tsunami deposits

    International Nuclear Information System (INIS)

    2013-01-01

    The NSC (the Nuclear Safety Commission of Japan) demand to survey on tsunami deposits by use of various technical methods (Dec. 2011), because tsunami deposits have useful information on tsunami activity, tsunami source etc. However, there are no guidelines on tsunami deposit survey in JAPAN. In order to prepare the guideline of tsunami deposits survey and evaluation and to develop the method of tsunami source estimation on the basis of tsunami deposits, JNES carried out the following issues; (1) organizing information of paleoseismological record and tsunami deposit by literature research, (2) field survey on tsunami deposit, and (3) designing the analysis code of sediment transport due to tsunami. As to (1), we organize the information gained about tsunami deposits in the database. As to (2), we consolidate methods for surveying and identifying tsunami deposits in the lake based on results of the field survey in Fukui Pref., carried out by JNES. In addition, as to (3), we design the experimental instrument for hydraulic experiment on sediment transport and sedimentation due to tsunamis. These results are reflected in the guideline on the tsunami deposits survey and evaluation. (author)

  19. Nutrient budgets for large Chinese estuaries

    Directory of Open Access Journals (Sweden)

    S. M. Liu

    2009-10-01

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

  20. Essential Nutrients, Feed Classification and Nutrient Content of Feeds

    OpenAIRE

    Hall, John Burton, 1960-; Seay, William W.; Baker, Scott M., 1968-

    2005-01-01

    The cow-calf herd's primary source of nutrition is forages, but forages are variable in nutrient content. By knowing the nutrient content of their base forages, producers can then identify the deficient nutrients that need to be supplemented.

  1. Menstrual Cycle

    Science.gov (United States)

    ... To receive General email updates Enter email Submit Menstrual Cycle The menstrual cycle is the hormonal process ... Preventing problems with your menstrual cycle View more Menstrual Cycle resources Related information Endometriosis Infertility Polycystic ovary ...

  2. Arbuscular mycorrhizal fungal species differ in their effect on nutrient leaching

    NARCIS (Netherlands)

    Köhl, Luise; van der Heijden, Marcel G A

    2016-01-01

    Arbuscular mycorrhizal (AM) fungi have been shown to play a crucial role in nutrient cycling and can reduce nutrient losses after rain induced leaching events. It is still unclear whether nutrient leaching losses vary depending on the AM fungal taxa that are present in soil. Using experimental

  3. Seasonal variability in nutrient regeneration by mussel Mytilus edulis rope culture in oligotrophic systems

    NARCIS (Netherlands)

    Jansen, H.M.; Strand, O.; Strohmeier, T.; Krogness, C.; Verdegem, M.C.J.; Smaal, A.C.

    2011-01-01

    Blue mussel Mytilus edulis cultures contribute to nutrient cycling in coastal ecosystems. Mussel populations filter particulate nutrients from the water column and inorganic nutrients are regenerated by excretion of metabolic wastes and decomposition of (pseudo-)faeces. The objective of this study

  4. Reactive nitrogen deposition to South East Asian rainforest

    Science.gov (United States)

    di Marco, Chiara F.; Phillips, Gavin J.; Thomas, Rick; Tang, Sim; Nemitz, Eiko; Sutton, Mark A.; Fowler, David; Lim, Sei F.

    2010-05-01

    The supply of reactive nitrogen (N) to global terrestrial ecosystems has doubled since the 1960s as a consequence of human activities, such as fertilizer application and production of nitrogen oxides by fossil-fuel burning. The deposition of atmospheric N species constitutes a major nutrient input to the biosphere. Tropical forests have been undergoing a radical land use change by increasing cultivation of sugar cane and oil palms and the remaining forests are increasingly affected by anthropogenic activities. Yet, quantifications of atmospheric nitrogen deposition to tropical forests, and nitrogen cycling under near-pristine and polluted conditions are rare. The OP3 project ("Oxidant and Particle Photochemical Processes above a Southeast Asian Tropical Rainforest") was conceived to study how emissions of reactive trace gases from a tropical rain forest mediate the regional scale production and processing of oxidants and particles, and to better understand the impact of these processes on local, regional and global scale atmospheric composition, chemistry and climate. As part of this study we have measured reactive, nitrogen containing trace gas (ammonia, nitric acid) and the associated aerosol components (ammonium, nitrate) at monthly time resolution using a simple filter / denuder for 16 months. These measurements were made at the Bukit Atur Global Atmospheric Watch tower near Danum Valley in the Malaysian state of Sabah, Borneo. In addition, the same compounds were measured at hourly time-resolution during an intensive measurement period, with a combination of a wet-chemistry system based on denuders and steam jet aerosol collectors and an aerosol mass spectrometer (HR-ToF-AMS), providing additional information on the temporal controls. During this period, concentrations and fluxes of NO, NO2 and N2O were also measured. The measurements are used for inferential dry deposition modelling and combined with wet deposition data from the South East Asian Acid

  5. Submarine groundwater discharge as a major source of nutrients to the Mediterranean Sea.

    Science.gov (United States)

    Rodellas, Valentí; Garcia-Orellana, Jordi; Masqué, Pere; Feldman, Mor; Weinstein, Yishai

    2015-03-31

    The Mediterranean Sea (MS) is a semienclosed basin that is considered one of the most oligotrophic seas in the world. In such an environment, inputs of allochthonous nutrients and micronutrients play an important role in sustaining primary productivity. Atmospheric deposition and riverine runoff have been traditionally considered the main external sources of nutrients to the MS, whereas the role of submarine groundwater discharge (SGD) has been largely ignored. However, given the large Mediterranean shore length relative to its surface area, SGD may be a major conveyor of dissolved compounds to the MS. Here, we used a (228)Ra mass balance to demonstrate that the total SGD contributes up to (0.3-4.8)⋅10(12) m(3) ⋅ y(-1) to the MS, which appears to be equal or larger by a factor of 16 to the riverine discharge. SGD is also a major source of dissolved inorganic nutrients to the MS, with median annual fluxes of 190⋅10(9), 0.7⋅10(9), and 110⋅10(9) mol for nitrogen, phosphorous, and silica, respectively, which are comparable to riverine and atmospheric inputs. This corroborates the profound implications that SGD may have for the biogeochemical cycles of the MS. Inputs of other dissolved compounds (e.g., iron, carbon) via SGD could also be significant and should be investigated.

  6. Nutrient attenuation in rivers and streams, Puget Sound Basin, Washington

    Science.gov (United States)

    Sheibley, Rich W.; Konrad, Christopher P.; Black, Robert W.

    2015-01-01

    Nutrients such as nitrogen and phosphorus are important for aquatic ecosystem health. Excessive amounts of nutrients, however, can make aquatic ecosystems harmful for biota because enhanced growth and decay cycles of aquatic algae can reduce dissolved oxygen in the water. In Puget Sound marine waters, low dissolved oxygen concentrations are observed in a number of marine nearshore areas, and nutrients have been identified as a major stressor to the local ecosystem. Delivery of nutrients from major rivers in the Puget Sound Basin to the marine environment can be large. Therefore, it is important to identify factors related to how nutrients are retained (attenuated) within streams and rivers in the Puget Sound Basin. Physical, chemical, and biological factors related to nutrient attenuation were identified through a review of related scientific literature.

  7. Modeling nutrient transports and exchanges of nutrients between shallow regions and the open Baltic sea in present and future climate.

    Science.gov (United States)

    Eilola, Kari; Rosell, Elin Almroth; Dieterich, Christian; Fransner, Filippa; Höglund, Anders; Meier, H E Markus

    2012-09-01

    We quantified horizontal transport patterns and the net exchange of nutrients between shallow regions and the open sea in the Baltic proper. A coupled biogeochemical-physical circulation model was used for transient simulations 1961-2100. The model was driven by regional downscaling of the IPCC climate change scenario A1B from two global General Circulation Models in combination with two nutrient load scenarios. Modeled nutrient transports followed mainly the large-scale internal water circulation and showed only small circulation changes in the future projections. The internal nutrient cycling and exchanges between shallow and deeper waters became intensified, and the internal removal of phosphorus became weaker in the warmer future climate. These effects counteracted the impact from nutrient load reductions according to the Baltic Sea Action Plan. The net effect of climate change and nutrient reductions was an increased net import of dissolved inorganic phosphorus to shallow areas in the Baltic proper.

  8. Nutrient addition effects on tropical dry forests: a mini-review from microbial to ecosystem scales

    Directory of Open Access Journals (Sweden)

    Jennifer S. Powers

    2015-06-01

    Full Text Available Humans have more than doubled inputs of reactive nitrogen globally and greatly accelerated the biogeochemical cycles of phosphorus and metals. However, the impacts of increased element mobility on tropical ecosystems remain poorly quantified, particularly for the vast tropical dry forest biome. Tropical dry forests are characterized by marked seasonality, relatively little precipitation, and high heterogeneity in plant functional diversity and soil chemistry. For these reasons, increased nutrient deposition may affect tropical dry forests differently than wet tropical or temperate forests. Here we review studies that investigated how nutrient availability affects ecosystem and community processes from the microsite to ecosystem scales in tropical dry forests. The effects of N and P addition on ecosystem carbon cycling and plant and microbial dynamics depend on forest successional stage, soil parent material and rainfall regime. Responses may depend on whether overall productivity is N- versus P-limited, although data to test this hypothesis are limited. These results highlight the many important gaps in our understanding of tropical dry forest responses to global change. Large-scale experiments are required to resolve these uncertainties.

  9. Nutrient addition effects on tropical dry forests: a mini-review from microbial to ecosystem scales

    Science.gov (United States)

    Powers, Jennifer; Becklund, Kristen; Gei, Maria; Iyengar, Siddarth; Meyer, Rebecca; O'Connell, Christine; Schilling, Erik; Smith, Christina; Waring, Bonnie; Werden, Leland

    2015-06-01

    Humans have more than doubled inputs of reactive nitrogen globally and greatly accelerated the biogeochemical cycles of phosphorus and metals. However, the impacts of increased element mobility on tropical ecosystems remain poorly quantified, particularly for the vast tropical dry forest biome. Tropical dry forests are characterized by marked seasonality, relatively little precipitation, and high heterogeneity in plant functional diversity and soil chemistry. For these reasons, increased nutrient deposition may affect tropical dry forests differently than wet tropical or temperate forests. Here we review studies that investigated how nutrient availability affects ecosystem and community processes from the microsite to ecosystem scales in tropical dry forests. The effects of N and P addition on ecosystem carbon cycling and plant and microbial dynamics depend on forest successional stage, soil parent material and rainfall regime. Responses may depend on whether overall productivity is N- versus P-limited, although data to test this hypothesis are limited. These results highlight the many important gaps in our understanding of tropical dry forest responses to global change. Large-scale experiments are required to resolve these uncertainties.

  10. Nutrient Content Claims

    Science.gov (United States)

    ... 8, 2014 Articles from Diabetes Forecast® magazine: wcie-nutrition, . In this section Food What Can I Eat Food Tips Eating Out Quick Meal Ideas Cutting Back on Sodium Nutrient Content Claims Snacks Taking ...

  11. Atmospheric Deposition And MediterraneAN sea water productiviTy (Thales - ADAMANT) An overview

    Science.gov (United States)

    Christodoulaki, Sylvia; Petihakis, George; Triantafyllou, George; Pitta, Paraskevi; Papadimitriou, Vassileios; Tsiaras, Konstantinos; Mihalopoulos, Nikolaos; Kanakidou, Maria

    2015-04-01

    In the marine environment the salinity and biological pumps sequester atmospheric carbon dioxide. The biological pump is directly related to marine primary production which is controlled by nutrient availability mainly of iron, nitrogen and phosphorus. The Mediterranean Sea, especially the eastern basin is one of the most oligotrophic seas. The nitrogen (N) to phosphorus (P) ratio is unusually high, especially in the eastern basin (28:1) and primary production is limited by phosphorus availability. ADAMANT project contributes to new knowledge into how nutrients enter the marine environment through atmospheric deposition, how they are assimilated by organisms and how this influences carbon and nutrient fluxes. Experimental work has been combined with atmospheric and marine models. Important knowledge is obtained on nutrients deposition through mesocosm experiments on their uptake by the marine systems and their effects on the marine carbon cycle and food chain. Kinetic parameters of adsorption of acidic and organic volatile compounds in atmospheric samples of dust and marine salts are estimated in conjunction with solubility of N and P in mixtures contained in dust. Atmospheric and oceanographic models are coupled to create a system that is able to holistically simulate the effects of atmospheric deposition on the marine environment over time, beginning from the pre-industrial era until the future years (hind cast, present and forecast simulations). This research has been co-financed by the European Union (European Social Fund) and Greek national funds through the Operational Program "Education and Lifelong Learning" of the National Strategic Reference Framework - Research Funding Program: THALES, Investing in knowledge society through European Social Fund.

  12. Linking soil and sediment properties for research on biogeochemical cycles

    Science.gov (United States)

    Kuhn, Nikolaus J.

    2013-04-01

    Conventional perspectives on soil erosion include the on-site damage to soil and reductions in crop yield, as well as the resulting off-site effects on water quality, runoff and sediment loads in rivers. Our evolving understanding of the Earth System has added a new dimension to the role of soil erosion within the global geochemical cycles. First, the relevance of soil as a nutrient and Carbon (C) pool was recognized. Initially, the role of soils in the global C cycle was largely considered to be limited to a vertical exchange of greenhouse house gases (GHG) between vegetation, soil and atmosphere and thus mostly studied by soil scientists, plant ecologists and climatologists. Even Critical Zone research focused mostly on weathering and regolith properties and ignored lateral fluxes of dissolved or particulate organic matter. Since the late 1990s, a wider role of soils in biogeochemical cycles has emerged. Recent estimates place the lateral movement of C between soil and sediment pools in terrestrial ecosystems (including rivers and lakes) at approximately 0.6 to 1.5 Gt per year. Some of the eroded C is replaced by photosynthesis from the atmosphere, but at a cost of additional emissions, for example due to fertilizer production. The long-term fate of the eroded and deposited soil organic matter is subject to an open debate and suffers from a lack of reliable spatial information on lateral C fluxes and its subsequent fate in terrestrial ecosystems. The connection between soil C pool, GHG emissions and erosion illustrates the relevance of surface processes for the C fluxes between Earth's spheres. Accordingly, soil is now considered as mobile system to make accurate predictions about the consequences of global change for terrestrial biogeochemical cycles and climate feedbacks. This expanded perspective on soils as dynamic pool of weathering regolith, sediment, nutrients and C at the interface between the geospheres requires the analysis of relevant soil properties

  13. Nutrient sequestration in Aquitaine lakes (SW France) limits nutrient flux to the coastal zone

    Science.gov (United States)

    Buquet, Damien; Anschutz, Pierre; Charbonnier, Céline; Rapin, Anne; Sinays, Rémy; Canredon, Axel; Bujan, Stéphane; Poirier, Dominique

    2017-12-01

    Oligotrophic coastal zones are disappearing from increased nutrient loading. The quantity of nutrients reaching the coast is determined not only by their original source (e.g. fertilizers used in agriculture, waste water discharges) and the land use, but also by the pathways through which nutrients are cycled from the source to the river mouth. In particular, lakes sequester nutrients and, hence, reduce downstream transfer of nutrients to coastal environments. Here, we quantify the impact of Aquitaine great lakes on the fluxes of dissolved macro-nutrients (N, P, Si) to the Bay of Biscay. For that, we have measured nutrient concentrations and fluxes in 2014 upstream and downstream lakes of Lacanau and Carcans-Hourtin, which belongs to the catchment of the Arcachon Bay, which is the largest coastal lagoon of the Bay of Biscay French coast. Data were compared to values obtained from the Leyre river, the main freshwater and nutrient source for the lagoon. Results show that processes in lakes greatly limit nutrient flux to the lagoon compared to fluxes from Leyre river, although the watershed is similar in terms of land cover. In lakes, phosphorus and silicon are trapped for long term in the sediment, silicon as amorphous biogenic silica and phosphorus as organic P and P associated with Fe-oxides. Nitrogen that enters lakes mostly as nitrate is used for primary production. N is mineralized in the sediment; a fraction diffuses as ammonium. N2 production through benthic denitrification extracts only 10% of dissolved inorganic nitrogen from the aquatic system. The main part is sequestered in organic-rich sediment that accumulates below 5 m depth in both lakes.

  14. Nutrient synchrony in preruminant calves

    NARCIS (Netherlands)

    Borne, van den J.J.G.C.

    2006-01-01

    In animal nutrition, the nutrient composition of the daily feed supply is composed to match the nutrient requirements for the desired performance. The time of nutrient availability within a day is usually considered not to affect the fate of nutrients. The aim of this thesis was to evaluate effects

  15. Nutrient uptake dynamics across a gradient of nutrient concentrations and ratios at the landscape scale

    Science.gov (United States)

    Gibson, Catherine A.; O'Reilly, Catherine M.; Conine, Andrea L.; Lipshutz, Sondra M.

    2015-02-01

    Understanding interactions between nutrient cycles is essential for recognizing and remediating human impacts on water quality, yet multielemental approaches to studying nutrient cycling in streams are currently rare. Here we utilized a relatively new approach (tracer additions for spiraling curve characterization) to examine uptake dynamics for three essential nutrients across a landscape that varied in absolute and relative nutrient availability. We measured nutrient uptake for soluble reactive phosphorous, ammonium-nitrogen, and nitrate-nitrogen in 16 headwater streams in the Catskill Mountains, New York. Across the landscape, ammonium-nitrogen and soluble reactive phosphorus had shorter uptake lengths and higher uptake velocities than nitrate-nitrogen. Ammonium-nitrogen and soluble reactive phosphorus uptake velocities were tightly correlated, and the slope of the relationship did not differ from one, suggesting strong demand for both nutrients despite the high ambient water column dissolved inorganic nitrogen: soluble reactive phosphorus ratios. Ammonium-nitrogen appeared to be the preferred form of nitrogen despite much higher nitrate-nitrogen concentrations. The uptake rate of nitrate-nitrogen was positively correlated with ambient soluble reactive phosphorus concentration and soluble reactive phosphorus areal uptake rate, suggesting that higher soluble reactive phosphorus concentrations alleviate phosphorus limitation and facilitate nitrate-nitrogen uptake. In addition, these streams retained a large proportion of soluble reactive phosphorus, ammonium-nitrogen, and nitrate-nitrogen supplied by the watershed, demonstrating that these streams are important landscape filters for nutrients. Together, these results (1) indicated phosphorus limitation across the landscape but similarly high demand for ammonium-nitrogen and (2) suggested that nitrate-nitrogen uptake was influenced by variability in soluble reactive phosphorus availability and preference for

  16. Integrated Urban Nutrient Management

    Science.gov (United States)

    Nhapi, I.; Veenstra, S.; Siebel, M. A.; Gijzen, H. J.

    Most cities, especially from the developing countries, are facing serious problems with the management of nutrients, necessitating an urgent review of current waste management systems. Whilst highly efficient technologies are available, the inclusion of these in a well-thought out and systematic approach is necessary to contain the nutrient influxes and outfluxes from towns. Five intervention measures are proposed in this paper. The first is to manage the use and generation of nutrients by drastically minimising water consumption and employing other cleaner production approaches. The second deals with the optimal reuse of nutrients and water at the smallest possible level, like at the household and on-plot level. The second option is to covert the waste into something useful for reuse, and, where not possible, to something which is envi- ronmentally neutral. This involves treatment, but applying technologies that makes the best use of side products via reuse. Where the first three options will have failed, two least preferred options could be used. Waste can be dispersed or diluted to enhance self-purification capacities of downstream water bodies. The last option is to store the wastewater for some parts of the year when there is water shortage to allow for polishing during the standing period. The success of urban nutrient planning requires an integrated approach, proving specific solutions to specific situations. This, in turn, requires appropriate institutional responses.

  17. Global nutrient transport in a world of giants.

    Science.gov (United States)

    Doughty, Christopher E; Roman, Joe; Faurby, Søren; Wolf, Adam; Haque, Alifa; Bakker, Elisabeth S; Malhi, Yadvinder; Dunning, John B; Svenning, Jens-Christian

    2016-01-26

    The past was a world of giants, with abundant whales in the sea and large animals roaming the land. However, that world came to an end following massive late-Quaternary megafauna extinctions on land and widespread population reductions in great whale populations over the past few centuries. These losses are likely to have had important consequences for broad-scale nutrient cycling, because recent literature suggests that large animals disproportionately drive nutrient movement. We estimate that the capacity of animals to move nutrients away from concentration patches has decreased to about 8% of the preextinction value on land and about 5% of historic values in oceans. For phosphorus (P), a key nutrient, upward movement in the ocean by marine mammals is about 23% of its former capacity (previously about 340 million kg of P per year). Movements by seabirds and anadromous fish provide important transfer of nutrients from the sea to land, totalling ∼150 million kg of P per year globally in the past, a transfer that has declined to less than 4% of this value as a result of the decimation of seabird colonies and anadromous fish populations. We propose that in the past, marine mammals, seabirds, anadromous fish, and terrestrial animals likely formed an interlinked system recycling nutrients from the ocean depths to the continental interiors, with marine mammals moving nutrients from the deep sea to surface waters, seabirds and anadromous fish moving nutrients from the ocean to land, and large animals moving nutrients away from hotspots into the continental interior.

  18. Swift recovery of Sphagnum nutrient concentrations after excess supply.

    Science.gov (United States)

    Limpens, Juul; Heijmans, Monique M P D

    2008-08-01

    Although numerous studies have addressed the effects of increased N deposition on nutrient-poor environments such as raised bogs, few studies have dealt with to what extent, and on what time-scale, reductions in atmospheric N supply would lead to recovery of the ecosystems in question. Since a considerable part of the negative effects of elevated N deposition on raised bogs can be related to an imbalance in tissue nutrient concentrations of the dominant peat-former Sphagnum, changes in Sphagnum nutrient concentration after excess N supply may be used as an early indicator of ecosystem response. This study focuses on the N and P concentrations of Sphagnum magellanicum and Sphagnum fallax before, during and after a factorial fertilization experiment with N and P in two small peatlands subject to a background bulk deposition of 2 g N m(-2) year(-1). Three years of adding N (4.0 g N m(-2) year(-1)) increased the N concentration, and adding P (0.3 g P m(-2) year(-1)) increased the P concentration in Sphagnum relative to the control treatment at both sites. Fifteen months after the nutrient additions had ceased, N concentrations were similar to the control whereas P concentrations, although strongly reduced, were still slightly elevated. The changes in the N and P concentrations were accompanied by changes in the distribution of nutrients over the capitulum and the stem and were congruent with changes in translocation. Adding N reduced the stem P concentration, whereas adding P reduced the stem N concentration in favor of the capitulum. Sphagnum nutrient concentrations quickly respond to reductions in excess nutrient supply, indicating that a management policy aimed at reducing atmospheric nutrient input to bogs can yield results within a few years.

  19. The pitcher plant Sarracenia purpurea can directly acquire organic nitrogen and short-circuit the inorganic nitrogen cycle.

    Directory of Open Access Journals (Sweden)

    Jim D Karagatzides

    2009-07-01

    Full Text Available Despite the large stocks of organic nitrogen in soil, nitrogen availability limits plant growth in many terrestrial ecosystems because most plants take up only inorganic nitrogen, not organic nitrogen. Although some vascular plants can assimilate organic nitrogen directly, only recently has organic nitrogen been found to contribute significantly to the nutrient budget of any plant. Carnivorous plants grow in extremely nutrient-poor environments and carnivory has evolved in these plants as an alternative pathway for obtaining nutrients. We tested if the carnivorous pitcher plant Sarracenia purpurea could directly take up intact amino acids in the field and compared uptake of organic and inorganic forms of nitrogen across a gradient of nitrogen deposition. We hypothesized that the contribution of organic nitrogen to the nitrogen budget of the pitcher plant would decline with increasing nitrogen deposition.At sites in Canada (low nitrogen deposition and the United States (high nitrogen deposition, individual pitchers were fed two amino acids, glycine and phenylalanine, and inorganic nitrogen (as ammonium nitrate, individually and in mixture. Plants took up intact amino acids. Acquisition of each form of nitrogen provided in isolation exceeded uptake of the same form in mixture. At the high deposition site, uptake of organic nitrogen was higher than uptake of inorganic nitrogen. At the low deposition site, uptake of all three forms of nitrogen was similar. Completeness of the associated detritus-based food web that inhabits pitcher-plant leaves and breaks down captured prey had no effect on nitrogen uptake.By taking up intact amino acids, Sarracenia purpurea can short-circuit the inorganic nitrogen cycle, thus minimizing potential bottlenecks in nitrogen availability that result from the plant's reliance for nitrogen mineralization on a seasonally reconstructed food web operating on infrequent and irregular prey capture.

  20. A rapidly deposited pennate diatom ooze in Upper Miocene-Lower Pliocene sediment beneath the North Pacific polar front

    Science.gov (United States)

    Dickens, G.R.; Barron, J.A.

    1997-01-01

    Rapidly deposited Thalassionema-Thalassiothrix pennate diatom oozes previously have been described in Upper Miocene-Lower Pliocene sediment beneath the frontal boundary of the eastern equatorial Pacific. Here we document a new occurrence of Thalassionema-Thalassiothrix ooze in Upper Miocene Lower Pliocene sediment beneath the frontal boundary of the subarctic North Pacific. The ooze is a 6 m interval of siliceous sediment at Ocean Drilling Program (ODP) sites 885/886 that was rapidly deposited between approximately 5.0 and 5.9 Ma. Bulk sediment in this interval may contain greater than 85% pennate diatom tests. There are also abundant laminae and pockets that are composed entirely of Thalassionema and Thalassiothrix diatoms. The presence of a rapidly deposited ooze dominated by pennate diatoms indicates unusual past conditions in the overlying surface waters. Time coincident deposition of such oozes at two distinct frontal boundary locations of the Pacific suggests that the unusual surface water conditions were causally linked to large-scale oceanographic change. This same oceanographic change most likely involved (1) addition of nutrients to the ocean, or (2) redistribution of nutrients within the ocean. The occurrence and origin of pennate diatom oozes may be a key component to an integrative understanding of late Neogene paleoceanography and biogeochemical cycling.

  1. Ciclagem de nutrientes via precipitação pluvial total, interna e escoamento pelo tronco em sistema agroflorestal com Gliricidia sepium Nutrient cycling through rainfall, throughfall and stemflow in an agroforestry system with Gliricidia sepium in semi-arid Paraiba, Brazil

    Directory of Open Access Journals (Sweden)

    Aldrin Martin Perez-Marin

    2008-12-01

    Full Text Available A deposição de nutrientes contidos na água de chuva que passa pela copa das árvores e que escoa pelo tronco até o solo pode constituir uma via importante da ciclagem biogeoquímica em sistemas agroflorestais de baixo uso de insumos externos. Todavia, não há informação disponível sobre esses processos em agroecossistemas da região semi-árida do Nordeste brasileiro. O presente trabalho foi conduzido em um sistema agroflorestal de cultivo em aléias, com gliricídia e milho, em Esperança, PB, e teve como objetivo quantificar: a proporção da água de chuva que escoa através da copa das árvores, ou pelo tronco, ou que é interceptada pela copa; e as entradas de N, P e K contidos na água escoada através da copa ou pelo tronco, bem como na água de chuva em áreas sem árvores. Na área experimental, foram delimitadas quatro parcelas, onde foram instalados coletores a 0,50 m de distância do tronco das árvores de gliricídia e coletores tipo ´colarinho´ acoplados ao redor do tronco destas. Paralelamente, foram instalados coletores em áreas adjacentes, sem árvores, para quantificação da precipitação pluvial total. Da precipitação pluvial total, 67 % escoou através da copa , 0,74 % escoou pelo tronco e 32 % foi interceptada pela copa das árvores. As concentrações de N e P foram similares nas amostras da água escoada através da copa ou pelo tronco, porém estas foram cerca de 300 % maiores do que na água de chuva. A concentração de K na água escoada pelo tronco foi cerca de 100 e 600 % maior do que na água escoada através da copa e na água de chuva, respectivamente. Em média, os aportes de N, P e K ao solo foram de 5, 1 e 24 kg ha-1 na água de chuva; 9, 2 e 62 kg ha-1 na água escoada através da copa; e 0,12, 0,02 e 1 kg ha-1 na água escoada pelo tronco, respectivamente. Os resultados demonstram a importância da adoção de sistemas agroflorestais para a sustentabilidade de sistemas agrícolas de baixo uso

  2. Megafauna moves nutrients uphill.

    Science.gov (United States)

    Gross, Michael

    2016-01-11

    Large animals have a disproportionate capacity to transport nutrients along gradients and against water flow directions, making them more available to ecosystems and ultimately saving them from disappearing in sea floor sediments. Megafauna extinctions have reduced this capacity dramatically, while humans and their livestock aren’t stepping in to restore this important ecosystem service.

  3. Infiltration deposits

    International Nuclear Information System (INIS)

    Khasanov, A.Kh.

    1988-01-01

    Infiltration deposits-is concentration of minerals matters formed by concretion on the some depth of readily soluble of descending waters of hyper genes zone. In the process of rocks chemical decomposition a great deal of readily soluble components in the form of sulfates, carbonates, bicarbonates, hydro-oxides and complex compounds, including ore element compounds become free

  4. Streamwater chemistry and nutrient budgets for forested watersheds in New England: variability and management implications

    Science.gov (United States)

    J.W. Hornbeck; S.W. Bailey; D.C. Buso; J.B. Shanley

    1997-01-01

    Chemistry of precipitation and streamwater and resulting input-output budgets for nutrient ions were determined concurrently for three years on three upland, forested watersheds located within an 80 km radius in central New England. Chemistry of precipitation and inputs of nutrients via wet deposition were similar among the three watersheds and were generally typical...

  5. Nutrient Dynamics of Estuarine Invertebrates Are Shaped by Feeding Guild Rather than Seasonal River Flow.

    Science.gov (United States)

    Ortega-Cisneros, Kelly; Scharler, Ursula M

    2015-01-01

    This study aimed to determine the variability of carbon and nitrogen elemental content, stoichiometry and diet proportions of invertebrates in two sub-tropical estuaries in South Africa experiencing seasonal changes in rainfall and river inflow. The elemental ratios and stable isotopes of abiotic sources, zooplankton and macrozoobenthos taxa were analyzed over a dry/wet seasonal cycle. Nutrient content (C, N) and stoichiometry of suspended particulate matter exhibited significant spatio-temporal variations in both estuaries, which were explained by the variability in river inflow. Sediment particulate matter (%C, %N and C:N) was also influenced by the variability in river flow but to a lesser extent. The nutrient content and ratios of the analyzed invertebrates did not significantly vary among seasons with the exception of the copepod Pseudodiaptomus spp. (C:N) and the tanaid Apseudes digitalis (%N, C:N). These changes did not track the seasonal variations of the suspended or sediment particulate matter. Our results suggest that invertebrates managed to maintain their stoichiometry independent of the seasonality in river flow. A significant variability in nitrogen content among estuarine invertebrates was recorded, with highest % N recorded from predators and lowest %N from detritivores. Due to the otherwise general lack of seasonal differences in elemental content and stoichiometry, feeding guild was a major factor shaping the nutrient dynamics of the estuarine invertebrates. The nutrient richer suspended particulate matter was the preferred food source over sediment particulate matter for most invertebrate consumers in many, but not all seasons. The most distinct preference for suspended POM as a food source was apparent from the temporarily open/closed system after the estuary had breached, highlighting the importance of river flow as a driver of invertebrate nutrient dynamics under extreme events conditions. Moreover, our data showed that estuarine

  6. COTYLEDONOUS DEPOSITS OF PRIDE OF BARBADOS

    African Journals Online (AJOL)

    BSN

    Ascorbic acid and microbiological analyses of extra - cotyledonous deposits of Pride of Barbados. (Caesalpina pulcherrima) stored at various temperatures were investigated. 2,6 - Dichlorophenolindophenol (dye) solution titration method was used in ascorbic acid determination while. Nutrient and Sabouraud agar were ...

  7. Late gestational nutrient restriction

    DEFF Research Database (Denmark)

    Tygesen, Malin Plumhoff; Nielsen, Mette Olaf; Nørgaard, Peder

    2008-01-01

    We investigated the effect of 50% nutrient restriction during the last 6 weeks of gestation on twin-pregnant ewes' plasma glucose, non-esterified fatty acid, ß-hydroxybutyrate, insulin, IGF-1 and leptin concentrations and the effects on lamb birth weight and ewes' lactation performance. Plasma...... metabolite and hormone concentrations in restricted ewes suggest that maternal tissues were being mobilised. Despite the ewes' adaptations their lambs weighed significantly less at birth. Furthermore, colostrum and milk yields were markedly reduced up until the latest measurement at 3 weeks post partum...... despite adlibitum access to feed. Reduced milk yields coincided with reduced plasma IGF-1 concentration pre partum in nutrient restricted ewes indicating, that mammary gland development may have been compromised. The present data suggest that leptin is not involved in the regulation of early lactation...

  8. Nutrients in the nexus

    Science.gov (United States)

    Davidson, Eric A.; Niphong, Rachel; Ferguson, Richard B.; Palm, Cheryl; Osmond, Deanna L.; Baron, Jill S.

    2016-01-01

    Synthetic nitrogen (N) fertilizer has enabled modern agriculture to greatly improve human nutrition during the twentieth century, but it has also created unintended human health and environmental pollution challenges for the twenty-first century. Averaged globally, about half of the fertilizer-N applied to farms is removed with the crops, while the other half remains in the soil or is lost from farmers’ fields, resulting in water and air pollution. As human population continues to grow and food security improves in the developing world, the dual development goals of producing more nutritious food with low pollution will require both technological and socio-economic innovations in agriculture. Two case studies presented here, one in sub-Saharan Africa and the other in Midwestern United States, demonstrate how management of nutrients, water, and energy is inextricably linked in both small-scale and large-scale food production, and that science-based solutions to improve the efficiency of nutrient use can optimize food production while minimizing pollution. To achieve the needed large increases in nutrient use efficiency, however, technological developments must be accompanied by policies that recognize the complex economic and social factors affecting farmer decision-making and national policy priorities. Farmers need access to affordable nutrient supplies and support information, and the costs of improving efficiencies and avoiding pollution may need to be shared by society through innovative policies. Success will require interdisciplinary partnerships across public and private sectors, including farmers, private sector crop advisors, commodity supply chains, government agencies, university research and extension, and consumers.

  9. Deposition of sediment from suspension in emergent vegetation ...

    African Journals Online (AJOL)

    Emergent instream vegetation influences the transport and deposition of suspended sediment in rivers, and hence their morphology and nutrient dynamics. An experimental laboratory study has shown how emergent vegetation stems promote sediment deposition. The suspended transport and the extent of longitudinal ...

  10. Bone nutrients for vegetarians.

    Science.gov (United States)

    Mangels, Ann Reed

    2014-07-01

    The process of bone mineralization and resorption is complex and is affected by numerous factors, including dietary constituents. Although some dietary factors involved in bone health, such as calcium and vitamin D, are typically associated with dairy products, plant-based sources of these nutrients also supply other key nutrients involved in bone maintenance. Some research suggests that vegetarian diets, especially vegan diets, are associated with lower bone mineral density (BMD), but this does not appear to be clinically significant. Vegan diets are not associated with an increased fracture risk if calcium intake is adequate. Dietary factors in plant-based diets that support the development and maintenance of bone mass include calcium, vitamin D, protein, potassium, and soy isoflavones. Other factors present in plant-based diets such as oxalic acid and phytic acid can potentially interfere with absorption and retention of calcium and thereby have a negative effect on BMD. Impaired vitamin B-12 status also negatively affects BMD. The role of protein in calcium balance is multifaceted. Overall, calcium and protein intakes in accord with Dietary Reference Intakes are recommended for vegetarians, including vegans. Fortified foods are often helpful in meeting recommendations for calcium and vitamin D. Plant-based diets can provide adequate amounts of key nutrients for bone health. © 2014 American Society for Nutrition.

  11. Integrated Assessment of Ecosystem Effects of Atmospheric Deposition

    Science.gov (United States)

    Ecosystems obtain a portion of their nutrients from the atmosphere. Following the Industrial Revolution, however, human activities have accelerated biogeochemical cycles, greatly enhancing the transport of substances among the atmosphere, water, soil, and living things. The atmos...

  12. Nutrient budgets for large Chinese estuaries and embayment

    Science.gov (United States)

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

    2009-01-01

    that in the winter. In the embayment, the exchange flow dominated the water budgets, resulting in average system salinity approaching the China seas salinity where river discharge is limited. The major Chinese estuaries and embayment transport 1.0-3.1% of nitrogen, 0.2-0.5% of phosphorus and 3% of silicon necessary for phytoplankton growth for the China Seas. This demonstrates regenerated nutrients in water column and sediments and nutrients transport fluxes between the China Seas and open ocean play an important role for phytoplankton growth. Atmospheric deposition may be another important source of nutrients for the China Seas.

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

    Directory of Open Access Journals (Sweden)

    Dag O. Hessen

    2013-03-01

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

  14. Nitrogen deposition and sensitive ecosystems: a case study from the San Francisco Bay Area

    Science.gov (United States)

    Weiss, S. B.

    2001-12-01

    Nitrogen deposition from urban smog can greatly affect local ecosystems. This paper examines a complex situation in the Santa Clara Valley, CA where N-deposition from existing, new, and proposed developments threatens an ecosystem supporting numerous rare, threatened, and endangered species. Grasslands on nutrient-poor serpentinitic soils are being invaded by nutrient-demanding introduced annual grasses, driven by dry N-deposition of about 10 kg ha-1 yr-1. These grass invasions threaten the native biodiversity of the serpentinitic grasslands, including the federally-protected Bay checkerspot butterfly. Additional NOx and NH3 sources planned for the region include a 600 MW natural gas fired power plant, industrial parks that may eventually draw 20,000 to 50,000 additional cars per day, 25,000 housing units, and associated highway improvements. Ongoing mitigation proposals include purchase and long-term management of hundreds of hectares of habitat. The situation is a model for understanding N-deposition from a scientific and policy viewpoint. Fundamental biogeochemical questions include: 1) What are the relative contributions of NOx and NH3 to increased N-deposition? NH3 slip from power plant NOx scrubbers can release more reactive nitrogen than is removed as NOx, and modern automobiles release NH3 in addition to NOx. 2) How are N-emissions transported, chemically modified, and deposited on the local ecosystems, and are these processes adequately captured in regulatory models? How do point sources differ from line sources such as a heavily traveled freeway? 3) What are the effects of chronic N-deposition on the ecosystem, and is there a critical load or a steady cumulative effect? 4) What are the effects of management such as fire, grazing, mowing on N-cycling and plant composition? Policy issues include: 1) What are the incremental impacts of individual projects relative to high background deposition, 2) What margin of safety should be built into modeling and

  15. A global assessment of precipitation chemistry and deposition of sulfur, nitrogen, sea salt, base cations, organic acids, acidity and pH, and phosphorus

    Science.gov (United States)

    Vet, Robert; Artz, Richard S.; Carou, Silvina

    2014-08-01

    Investigating and assessing the chemical composition of precipitation and atmospheric deposition is essential to understanding how atmospheric pollutants contribute to contemporary environmental concerns including ecosystem acidification and eutrophication, loss of biodiversity, air pollution and global climate change. Evidence of the link between atmospheric deposition and these environmental issues is well established. The state of scientific understanding of this link is that present levels of atmospheric deposition of sulfur and nitrogen adversely affect terrestrial and aquatic ecosystems, putting forest sustainability and aquatic biodiversity at risk. Nitrogen and phosphorus loadings are linked to impacts on the diversity of terrestrial and aquatic vegetation through biological cycling, and atmospheric deposition plays a major role in the emission-transport-conversion-loss cycle of chemicals in the atmosphere as well as the formation of particulate matter and ozone in the troposphere. Evidence also shows that atmospheric constituents are changing the earth's climate through direct and indirect atmospheric processes. This Special Issue, comprising a single article titled "A global assessment of precipitation chemistry and deposition of sulfur, nitrogen, sea salt, base cations, organic acids, acidity and pH, and phosphorus", presents a recent comprehensive review of precipitation chemistry and atmospheric deposition at global and regional scales. The information in the Special Issue, including all supporting data sets and maps, is anticipated to be of great value not only to the atmospheric deposition community but also to other science communities including those that study ecosystem impacts, human health effects, nutrient processing, climate change, global and hemispheric modeling and biogeochemical cycling. Understanding and quantifying pollutant loss from the atmosphere is, and will remain, an important component of each of these scientific fields as they

  16. Iron-light colimitation in a global ocean biogeochemical model and the sensitivity of oceanic CO2 uptake to dust deposition

    Science.gov (United States)

    Nickelsen, L.; Oschlies, A.

    2012-12-01

    The iron hypothesis of glacial-interglacial cycles states that glacial increases in the deposition of dust enhanced the concentrations of the micronutrient iron in the ocean where it triggered phytoplankton growth and thus CO2 uptake. Indeed, iron fertilization experiments find that phytoplankton needs iron in particular for nitrate uptake, light harvesting, synthesis of chlorophyll and in the electron transport chain of photosynthesis. Previous global biogeochemical models used to extrapolate results from local culture and field experiments have suggested that the sensitivity of ocean biogeochemistry to changes in dust deposition is too low to account for the observed glacial-interglacial changes of atmospheric CO2 concentrations. Here we show that this sensitivity is increased significantly when iron-light colimitation, i.e. the impact of iron on light harvesting capabilities and chlorophyll synthesis, is explicitly considered in a global biogeochemical ocean model. Iron-light colimitation increases the shift of export production to higher latitudes at high dust deposition and amplifies iron limitation at low dust deposition. Our results suggest that iron fertilization by increased dust deposition may explain a substantially larger portion of the observed past CO2 variability than thought previously. Our results emphasize the role of iron as a key limiting nutrient for phytoplankton in the ocean, with a high potential for changes in oceanic iron supply affecting the global carbon cycle and climate.

  17. Spatial redistribution of nutrients by large herbivores and dung beetles in a savanna ecosystem

    NARCIS (Netherlands)

    Veldhuis, Michiel P.; Gommers, Moniek I.; Olff, Han; Berg, Matty P.

    1. Territorial or resting behaviour of large herbivores can cause strong local deposits of dung, in different places than where they graze. Additionally, dung beetles and other macrodetritivores can subsequently affect local nutrient budgets through post-depositional re-dispersion of dung and

  18. Aggregated filter-feeding consumers alter nutrient limitation: consequences for ecosystem and community dynamics.

    Science.gov (United States)

    Atkinson, Carla L; Vaughn, Caryn C; Forshay, Kenneth J; Cooper, Joshua T

    2013-06-01

    Nutrient cycling is a key process linking organisms in ecosystems. This is especially apparent in stream environments in which nutrients are taken up readily and cycled through the system in a downstream trajectory. Ecological stoichiometry predicts that biogeochemical cycles of different elements are interdependent because the organisms that drive these cycles require fixed ratios of nutrients. There is growing recognition that animals play an important role in biogeochemical cycling across ecosystems. In particular, dense aggregations of consumers can create biogeochemical hotspots in aquatic ecosystems via nutrient translocation. We predicted that filter-feeding freshwater mussels, which occur as speciose, high-biomass aggregates, would create biogeochemical hotspots in streams by altering nutrient limitation and algal dynamics. In a field study, we manipulated nitrogen and phosphorus using nutrient-diffusing substrates in areas with high and low mussel abundance, recorded algal growth and community composition, and determined in situ mussel excretion stoichiometry at 18 sites in three rivers (Kiamichi, Little, and Mountain Fork Rivers, south-central United States). Our results indicate that mussels greatly influence ecosystem processes by modifying the nutrients that limit primary productivity. Sites without mussels were N-limited with -26% higher relative abundances of N-fixing blue-green algae, while sites with high mussel densities were co-limited (N and P) and dominated by diatoms. These results corroborated the results of our excretion experiments; our path analysis indicated that mussel excretion has a strong influence on stream water column N:P. Due to the high N:P of mussel excretion, strict N-limitation was alleviated, and the system switched to being co-limited by both N and P. This shows that translocation of nutrients by mussel aggregations is important to nutrient dynamics and algal species composition in these rivers. Our study highlights the

  19. Herbivores and nutrients control grassland plant diversity via light limitation

    Science.gov (United States)

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

    2014-01-01

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

  20. 9 Nutrient Load of the Sakumo Lagoon.cdr

    African Journals Online (AJOL)

    Administrator

    cycles of marine fish and prawn species, as well as fisheries further ... Pollution of the lagoon with nutrients can affect biodiversity of plant and animal species, especially water fowls and birds ecology, since the site is noted for its large number of birds (Ntiamoa- ... found along most of the river courses within the Ramsar site.

  1. Stoichiometric patterns in foliar nutrient resorption across multiple scales

    Science.gov (United States)

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

    2012-01-01

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

  2. Dopamine alleviates nutrient deficiency-induced stress in Malus hupehensis.

    Science.gov (United States)

    Liang, Bowen; Li, Cuiying; Ma, Changqing; Wei, Zhiwei; Wang, Qian; Huang, Dong; Chen, Qi; Li, Chao; Ma, Fengwang

    2017-10-01

    Dopamine mediates many physiological processes in plants. We investigated its role in regulating growth, root system architecture, nutrient uptake, and responses to nutrient deficiencies in Malus hupehensis Rehd. Under a nutrient deficiency, plants showed significant reductions in growth, chlorophyll concentrations, and net photosynthesis, along with disruptions in nutrient uptake, transport, and distribution. However, pretreatment with 100 μM dopamine markedly alleviated such inhibitions. Supplementation with that compound enabled plants to maintain their photosynthetic capacity and development of the root system while promoting the uptake of N, P, K, Ca, Mg, Fe, Mn, Cu, Zn, and B, altering the way in which those nutrients were partitioned throughout the plant. The addition of dopamine up-regulated genes for antioxidant enzymes involved in the ascorbate-glutathione cycle (MdcAPX, MdcGR, MdMDHAR, MdDHAR-1, and MdDHAR-2) but down-regulated genes for senescence (SAG12, PAO, and MdHXK). These results indicate that exogenous dopamine has an important antioxidant and anti-senescence effect that might be helpful for improving nutrient uptake. Our findings demonstrate that dopamine offers new opportunities for its use in agriculture, especially when addressing the problem of nutrient deficiencies. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

  3. Carbon footprint of urban source separation for nutrient recovery.

    Science.gov (United States)

    Kjerstadius, H; Bernstad Saraiva, A; Spångberg, J; Davidsson, Å

    2017-07-15

    Source separation systems for the management of domestic wastewater and food waste has been suggested as more sustainable sanitation systems for urban areas. The present study used an attributional life cycle assessment to investigate the carbon footprint and potential for nutrient recovery of two sanitation systems for a hypothetical urban area in Southern Sweden. The systems represented a typical Swedish conventional system and a possible source separation system with increased nutrient recovery. The assessment included the management chain from household collection, transport, treatment and final return of nutrients to agriculture or disposal of the residuals. The results for carbon footprint and nutrient recovery (phosphorus and nitrogen) concluded that the source separation system could increase nutrient recovery (0.30-0.38 kg P capita -1 year -1 and 3.10-3.28 kg N capita -1 year -1 ), while decreasing the carbon footprint (-24 to -58 kg CO 2 -eq. capita -1 year -1 ), compared to the conventional system. The nutrient recovery was increased by the use of struvite precipitation and ammonium stripping at the wastewater treatment plant. The carbon footprint decreased, mainly due to the increased biogas production, increased replacement of mineral fertilizer in agriculture and less emissions of nitrous oxide from wastewater treatment. In conclusion, the study showed that source separation systems could potentially be used to increase nutrient recovery from urban areas, while decreasing the climate impact. Copyright © 2017 Elsevier Ltd. All rights reserved.

  4. Assessing the risk of nitrogen deposition to natural resources in the Four Corners area

    Science.gov (United States)

    Reed, Sasha C.; Belnap, Jayne; Floyd-Hanna, Lisa; Crews, Tim; Herring, Jack; Hanna, Dave; Miller, Mark E.; Duniway, Michael C.; Roybal, Carla M.

    2013-01-01

    Nitrogen (N) deposition in the western U.S. is on the rise and is already dramatically affecting terrestrial ecosystems. For example, N deposition has repeatedly been shown to lower air and water quality, increase greenhouse gas emissions, alter plant community composition, and significantly modify fire regimes. Accordingly, the effects of N deposition represent one of our largest environmental challenges and make difficult the National Park Service’s (NPS) important mission to “preserve the scenery and the natural and historic objects and the wildlife… unimpaired for the enjoyment of future generations”. Due to increased population growth and energy development (e.g., natural gas wells), the Four Corners region has become a notable ‘hotspot’ for N deposition. However, our understanding of how increased N deposition will affect these unique ecosystems, as well as how much deposition is actually occurring, remains notably poor. Here we used a multi-disciplinary approach to gathering information in an effort to help NPS safeguard the Four Corners national parks, both now and into the future. We applied modeling, field, and laboratory techniques to clarify current N deposition gradients and to help elucidate the ecosystem consequences of N deposition to the national parks of the Four Corners area. Our results suggest that NOx deposition does indeed represent a significant source of N to Mesa Verde National Park and, as expected, N deposition significantly affects coupled biogeochemical cycling (N, carbon, and phosphorus) of these landscapes. We also found some surprising results. For example, perhaps due to the low nutrient availability in these (and other) dryland ecosystems, although most other research suggests that adding N reduces N fixation rates, N additions did not consistently reduce natural N inputs via biological N2 fixation at our dryland sites. While the timeline of this pilot project is too brief to elucidate all the potential insight from

  5. Land-use and fire drive temporal patterns of soil solution chemistry and nutrient fluxes.

    Science.gov (United States)

    Potthast, Karin; Meyer, Stefanie; Crecelius, Anna C; Schubert, Ulrich S; Tischer, Alexander; Michalzik, Beate

    2017-12-15

    Land-use type and ecosystem disturbances are important drivers for element cycling and bear the potential to modulate soil processes and hence ecosystem functions. To better understand the effect of such drivers on the magnitude and temporal patterns of organic matter (OM) and associated nutrient fluxes in soils, continuous flux monitoring is indispensable but insufficiently studied yet. We conducted a field study to elucidate the impact of land-use and surface fires on OM and nutrient fluxes with soil solution regarding seasonal and temporal patterns analyzing short (Linear mixed model analyses exhibited that mean annual DOM and POM fluxes did not differ between the two land-use types, but were subjected to strong seasonal patterns. Fire disturbance significantly lowered the annual soil solution pH in both land-uses and increased water fluxes, while DOC fluxes remained unaffected. A positive response of POC and S to fire was limited to short-term effects, while amplified particulate and dissolved nitrogen fluxes were observed in the longer run and co-ocurred with accelerated Ca and Mg fluxes. In summary, surface fires generated stronger effects on element fluxes than the land-use. Fire-induced increases in POM fluxes suggest that the particulate fraction represent a major pathway of OM translocation into the subsoil and beyond. With regard to ecosystem functions, pasture ecosystems were less prone to the risk of nutrient losses following fire events than the forest. In pastures, fire-induced base cation export may accelerate soil acidification, consequently exhausting soil buffer systems and thus may reduce the resilience to acidic depositions and disturbances. Copyright © 2017 Elsevier B.V. All rights reserved.

  6. Nutrient losses from Fall and Winter-applied manure: Effects of timing and soil temperature

    Science.gov (United States)

    Soil temperature is a major environmental factor that affects both the infiltration of meltwater and precipitation, and nutrient cycling. The objectives of this study were to determine nutrient losses in runoff and leachate from fall and winter-applied dairy manure based on the soil temperature at t...

  7. Nutrient inputs to the coastal ocean through submarine groundwater discharge: controls and potential impact

    NARCIS (Netherlands)

    Slomp, C.P.; Van Cappellen, P.

    2004-01-01

    Nutrient input through submarine groundwater discharge (SGD) rivals river inputs in certain regions and may play a significant role in nutrient cycling and primary productivity in the coastal ocean. In this paper, we review the key factors determining the fluxes of nitrogen (N) and phosphorus (P)

  8. Nutrients removal using moving beds with aeration cycles

    International Nuclear Information System (INIS)

    Martin Martin, A.; Foresti, E.; Garcia-Encina, P. A.

    2009-01-01

    Moving Bed Biofilm Reactors (MBBR) are based on the biomass growth over a media that moves into the reactor due to aeration, mechanical agitation or recirculation. These reactors have been gaining popularity and they are employed in hundreds of plants everywhere with different treatment purposes (organic matter removal, nitrification/denitrification), both for urban and industrial wastewater. (Author)

  9. Dissecting the role of viruses in marine nutrient cycling

    DEFF Research Database (Denmark)

    Shelford, Emma J.; Jørgensen, Niels O. G.; Rasmussen, Susan

    2014-01-01

    Lysis of marine bacteria by viruses releases a range of organic compounds into the environment, including D- and L-amino acids, but the uptake of these compounds by other bacteria is not well characterized. This study determined that Photobacterium sp. strain SKA34 (Gamma - proteobacteria...... for Photobacterium sp. growth, thus causing a net uptake of ammonium. In contrast, only 1.51 μmol l−1 of the 4.77 μmol l−1 of the total dissolved combined amino acids (DCAAs) were taken up, indicating that a fraction of lysate-derived DCAAs were semi-labile or refractory to bacterial uptake. Both D- and L-amino acid...... uptake rates were approximately proportional to their concentrations, indicating similar availability for each enantiomer and unsaturated uptake rates. These results imply that under high C:N conditions, both D-amino acids (mainly found in bacterial cell walls) and L-amino acids (found in proteins...

  10. Development of Gene Centric Modeling for Nutrient Cycling

    Science.gov (United States)

    opportunity to participate in the development of a gene-centric model to help predict potential changes in the biogeochemistry of aquatic ecosystems that may arise from anthropogenic stressors and management decisions

  11. Nutrient cycling by Acacia erioloba (syn. Acacia giraffae ) in ...

    African Journals Online (AJOL)

    arid areas of Southern Africa because of the many benefits it offers to local communities. However, little quantitative plant and soil data exist to explain its ability to enhance soil fertility under local conditions. Paired soil samples taken under and ...

  12. Ecologically sustainable development in dairy farms II: Nutrient cycling

    Science.gov (United States)

    In Mexico, there is not a specific regulation dealing with manure and wastewater in confined livestock farms. In the case of dairy farms that have agricultural areas for the production of forage crops, there are some "Good Management Practices", focused on the use of manure as a source of nitrogen a...

  13. WERF Nutrient Challenge investigates limits of nutrient removal technologies.

    Science.gov (United States)

    Neethling, J B; Clark, D; Pramanik, A; Stensel, H D; Sandino, J; Tsuchihashi, R

    2010-01-01

    The WERF Nutrient Challenge is a multi-year collaborative research initiative established in 2007 to develop and provide current information about wastewater treatment nutrients (specifically nitrogen and phosphorus in wastewater), their characteristics, and bioavailability in aquatic environments to help regulators make informed decisions. The Nutrient Challenge will also provide data on nutrient removal so that treatment facilities can select sustainable, cost-effective methods and technologies to meet permit limits. To meet these goals, the Nutrient Challenge has teamed with a wide array of utilities, agencies, consultants, universities and other researchers and practitioners to collaborate on projects that advance these goals. The Nutrient Challenge is focusing on a different approach to collaborating and leveraging resources (financial and intellectual) on research projects by targeting existing projects and research that correspond with its goals and funding those aspects that the Nutrient Challenge identified as a priority. Because the Nutrient Challenge is focused on collaboration, outreach is an absolutely necessary component of its effectiveness. Through workshops, webinars, a web portal and online compendium, published papers, and conference lectures, the Nutrient Challenge is both presenting important new information, and soliciting new partnerships.

  14. Submarine groundwater discharge as an important nutrient source influencing nutrient structure in coastal water of Daya Bay, China

    Science.gov (United States)

    Wang, Xuejing; Li, Hailong; Zheng, Chunmiao; Yang, Jinzhong; Zhang, Yan; Zhang, Meng; Qi, Zhanhui; Xiao, Kai; Zhang, Xiaolang

    2018-03-01

    As an important nutrient source for coastal waters, submarine groundwater discharge (SGD) has long been largely ignored in Daya Bay, China. In this study, we estimate the fluxes of SGD and associated nutrients into this region using a 224Ra mass balance model and assess the contribution/importance of nutrients by SGD, benthic sediments, local rivers, and atmospheric deposition. The results of 224Ra mass balance show that the estimated SGD ranges from (2.76 ± 1.43) × 106 m3/d to (1.03 ± 0.53) × 107 m3/d with an average of (6.32 ± 2.42) × 106 m3/d, about 16 times the total discharge rate of local rivers. The nutrient loading from SGD is estimated to be (1.05-1.99) × 105 mol/d for NO3-N, (4.04-12.16) × 103 mol/d for DIP, and (3.54-11.35) × 105 mol/d for Si. Among these considered nutrient sources, we find that SGD is the primary source for Si and NO3-N, contributing 68% and 42% of all considered sources, respectively. The atmospheric NO3-N flux is comparable to that from SGD. The local rivers are the most important source for DIP, contributing 75% of all considered sources. SGD with high N:P ratio (NO3-N/DIP) of 37.0 delivers not only a large quantity of nutrients, but also changes nutrient structure in coastal water. Based on a DIP budget, primary productivity is evaluated to be 54-73 mg C/m2 d, in which SGD accounts for approximately 30% of total production. This study indicates that SGD is a key source of nutrients to coastal waters and may cause an obvious change of primary production and nutrient structure in Daya Bay.

  15. Hydro-climatic dominated on long-term input-output nutrient budget of subtropical forest ecosystem

    Science.gov (United States)

    Chang, C. T.; Wang, C. P.; Huang, J. C.; Lin, T. C.

    2016-12-01

    Two-decadal budget of atmospheric deposition (input) and streamwater export (output) from 1994 to 2013 were collected in a subtropical forest at northeastern Taiwan. There were significant decline trends of summer SO42- and NO3- fluxes (June-August), but not for the winter. With the identifications of possible sources of air pollutants from atmospheric backward trajectories model and local air quality observations, the declining of sulfate and nitrate in the summer was possibly due to decreases of local emissions of SO2 and NOx. In contrast, the non-declining long-range transport of acid species might contribute a large portion of the acid deposition in the winter and led to the lack of significant declining trends of SO42- and NO3- fluxes. The results suggest that long-range transport of acidic pollutants could be a threat to forest ecosystems in the region. The two-decadal budget also revealed that both input and output of ions were positively correlated with water quantity, indicating strong hydro-climatic dominated the input-output nutrient cycling. Especially for the greater ions export via stream water during the wet summer growing season, which is noticeably contrast to the paradigm of biological control resulting in low ions export during the growing season. Our study is of significant implication under the trends of warming climate because global climate change could directly affect biogeochemical cycles particularly in the tropical/subtropical ecosystems through amplifying the seasonal precipitation.

  16. Nutrient profiling for regulatory purposes.

    Science.gov (United States)

    Rayner, Mike

    2017-08-01

    In this paper, I first provide definitions of nutrient profiling and of a nutrient profile model. I set out the purposes of nutrient profiling: both general and specific. I give two examples of nutrient profile models that have been developed for regulatory purposes by the Food Standards Agency (FSA) in the UK and the WHO for its European Region - the UK FSA/Ofcom and the WHO-Euro models - and compare the way the models are constructed and function, how they have been developed, the extent to which they have been tested and validated and their use in regulation. Finally I draw some conclusions about the future use of nutrient profiling for regulatory purposes. I argue that its full potential has yet to be realised and give some reasons why. I pose some urgent research questions with respect to nutrient profiling.

  17. [Effects of biochar on soil nutrients leaching and potential mechanisms: A review].

    Science.gov (United States)

    Liu, Yu-xue; Lyu, Hao-hao; Shi, Yan; Wang, Yao-feng; Zhong, Zhe-ke; Yang, Sheng-mao

    2015-01-01

    Controlling soil nutrient leaching in farmland ecosystems has been a hotspot in the research field of agricultural environment. Biochar has its unique physical and chemical properties, playing a significant role in enhancing soil carbon storage, improving soil quality and increasing crop yield. As a kind of new exogenous material, biochar has the potential in impacting soil nutrient cycling directly or indirectly, and has profound influences on soil nutrient leaching. This paper analyzed the intrinsic factors affecting how biochar affects soil nutrient leaching, such as the physical and chemical properties of biochar, and the interaction between biochar and soil organisms. Then the latest literatures regarding the external factors, including biochar application rates, soil types, depth of soil layer, fertilization conditions and temporal dynamics, through which biochar influences soil nutrient (especially nitrogen and phosphorus) leaching were reviewed. On that basis, four related action mechanisms were clarified, including direct adsorption of nutrients by biochar due to its micropore structure or surface charge, influencing nutrient leaching through increasing soil water- holding capacity, influencing nutrient cycling through the interaction with soil microbes, and preferential transport of absorbed nutrients by fine biochar particles. At last future research directions for better understanding the interactions between biochar and nutrient leaching in the soil were proposed.

  18. An integrated decision support system for wastewater nutrient recovery and recycling to agriculture

    Science.gov (United States)

    Roy, E. D.; Bomeisl, L.; Cornbrooks, P.; Mo, W.

    2017-12-01

    Nutrient recovery and recycling has become a key research topic within the wastewater engineering and nutrient management communities. Several technologies now exist that can effectively capture nutrients from wastewater, and innovation in this area continues to be an important research pursuit. However, practical nutrient recycling solutions require more than capable nutrient capture technologies. We also need to understand the role that wastewater nutrient recovery and recycling can play within broader nutrient management schemes at the landscape level, including important interactions at the nexus of food, energy, and water. We are developing an integrated decision support system that combines wastewater treatment data, agricultural data, spatial nutrient balance modeling, life cycle assessment, stakeholder knowledge, and multi-criteria decision making. Our goals are to: (1) help guide design decisions related to the implementation of sustainable nutrient recovery technology, (2) support innovations in watershed nutrient management that operate at the interface of the built environment and agriculture, and (3) aid efforts to protect aquatic ecosystems while supporting human welfare in a circular nutrient economy. These goals will be realized partly through the assessment of plausible alternative scenarios for the future. In this presentation, we will describe the tool and focus on nutrient balance results for the New England region. These results illustrate that both centralized and decentralized wastewater nutrient recovery schemes have potential to transform nutrient flows in many New England watersheds, diverting wastewater N and P away from aquatic ecosystems and toward local or regional agricultural soils where they can offset a substantial percentage of imported fertilizer. We will also highlight feasibility criteria and next steps to integrate stakeholder knowledge, economics, and life cycle assessment into the tool.

  19. Trees and Streets as Drivers of Urban Stormwater Nutrient Pollution.

    Science.gov (United States)

    Janke, Benjamin D; Finlay, Jacques C; Hobbie, Sarah E

    2017-09-05

    Expansion of tree cover is a major management goal in cities because of the substantial benefits provided to people, and potentially to water quality through reduction of stormwater volume by interception. However, few studies have addressed the full range of potential impacts of trees on urban runoff, which includes deposition of nutrient-rich leaf litter onto streets connected to storm drains. We analyzed the influence of trees on stormwater nitrogen and phosphorus export across 19 urban watersheds in Minneapolis-St. Paul, MN, U.S.A., and at the scale of individual streets within one residential watershed. Stormwater nutrient concentrations were highly variable across watersheds and strongly related to tree canopy over streets, especially for phosphorus. Stormwater nutrient loads were primarily related to road density, the dominant control over runoff volume. Street canopy exerted opposing effects on loading, where elevated nutrient concentrations from trees near roads outweighed the weak influence of trees on runoff reduction. These results demonstrate that vegetation near streets contributes substantially to stormwater nutrient pollution, and therefore to eutrophication of urban surface waters. Urban landscape design and management that account for trees as nutrient pollution sources could improve water quality outcomes, while allowing cities to enjoy the myriad benefits of urban forests.

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

    Directory of Open Access Journals (Sweden)

    Yan Zhao

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

  1. Mechanisms of nitrogen deposition effects on temperate forest lichens and trees

    Science.gov (United States)

    Carter, Therese S.; Clark, Christopher M.; Fenn, Mark E.; Jovan, Sarah E.; Perakis, Steven; Riddell, Jennifer; Schaberg, Paul G.; Greaver, Tara; Hastings, Meredith

    2017-01-01

    We review the mechanisms of deleterious nitrogen (N) deposition impacts on temperate forests, with a particular focus on trees and lichens. Elevated anthropogenic N deposition to forests has varied effects on individual organisms depending on characteristics both of the N inputs (form, timing, amount) and of the organisms (ecology, physiology) involved. Improved mechanistic knowledge of these effects can aid in developing robust predictions of how organisms respond to either increases or decreases in N deposition. Rising N levels affect forests in micro- and macroscopic ways from physiological responses at the cellular, tissue, and organism levels to influencing individual species and entire communities and ecosystems. A synthesis of these processes forms the basis for the overarching themes of this paper, which focuses on N effects at different levels of biological organization in temperate forests. For lichens, the mechanisms of direct effects of N are relatively well known at cellular, organismal, and community levels, though interactions of N with other stressors merit further research. For trees, effects of N deposition are better understood for N as an acidifying agent than as a nutrient; in both cases, the impacts can reflect direct effects on short time scales and indirect effects mediated through long-term soil and belowground changes. There are many gaps on fundamental N use and cycling in ecosystems, and we highlight the most critical gaps for understanding potential deleterious effects of N deposition. For lichens, these gaps include both how N affects specific metabolic pathways and how N is metabolized. For trees, these gaps include understanding the direct effects of N deposition onto forest canopies, the sensitivity of different tree species and mycorrhizal symbionts to N, the influence of soil properties, and the reversibility of N and acidification effects on plants and soils. Continued study of how these N response mechanisms interact with one

  2. Nutrients and neurodevelopment: lipids.

    Science.gov (United States)

    González, Horacio F; Visentin, Silvana

    2016-10-01

    Nutrients, lipids in particular, make up the central nervous system structure and play major functional roles: they stimulate development, migration, and nerve cell differentiation. They are part of gray matter, white matter, nerve nuclei, and synaptogenesis. Breast milk contains lipids which are crucial for infant brain development. The lipid profile of breast milk was used as a guideline for the development of breast milk substitutes. However, to date, no substitute has matched it. Complementary feeding should include docosahexaenoic acid, arachidonic acid, other polyunsaturated fatty acids, saturated fatty acids, and complex lipids found in milk fat. The lipid composition of breast milk depends on maternal intake and nutritional status during pregnancy and breast-feeding. It has a great impact on development. Our goal is to review scientific literature regarding the role of lipids on infant brain development and the importance of breast milk lipid composition, maternal diet, and complementary feeding. Sociedad Argentina de Pediatría.

  3. Dust deposition: iron source or sink? A case study

    Directory of Open Access Journals (Sweden)

    Y. Ye

    2011-08-01

    Full Text Available A significant decrease of dissolved iron (DFe concentration has been observed after dust addition into mesocosms during the DUst experiment in a low Nutrient low chlorophyll Ecosystem (DUNE, carried out in the summer of 2008. Due to low biological productivity at the experiment site, biological consumption of iron can not explain the magnitude of DFe decrease. To understand processes regulating the observed DFe variation, we simulated the experiment using a one-dimensional model of the Fe biogeochemical cycle, coupled with a simple ecosystem model. Different size classes of particles and particle aggregation are taken into account to describe the particle dynamics. DFe concentration is regulated in the model by dissolution from dust particles and adsorption onto particle surfaces, biological uptake, and photochemical mobilisation of particulate iron.

    The model reproduces the observed DFe decrease after dust addition well. This is essentially explained by particle adsorption and particle aggregation that produces a high export within the first 24 h. The estimated particle adsorption rates range between the measured adsorption rates of soluble iron and those of colloidal iron, indicating both processes controlling the DFe removal during the experiment. A dissolution timescale of 3 days is used in the model, instead of an instantaneous dissolution, underlining the importance of dissolution kinetics on the short-term impact of dust deposition on seawater DFe.

    Sensitivity studies reveal that initial DFe concentration before dust addition was crucial for the net impact of dust addition on DFe during the DUNE experiment. Based on the balance between abiotic sinks and sources of DFe, a critical DFe concentration has been defined, above which dust deposition acts as a net sink of DFe, rather than a source. Taking into account the role of excess iron binding ligands and biotic processes, the critical DFe concentration might be applied to

  4. Nutrient and Anti nutrient Composition of Jams Prepared from ...

    African Journals Online (AJOL)

    Objective: This study was aimed at determining the nutrient and anti nutrient composition of jams prepared from Hibiscus sabdariffa calyx extract Materials and methods: Hibiscus sabdariffa calyx, otherwise known as Red Roselle usually processed into a refreshing drink “Zobo” in Nigeria was extracted with distilled water ...

  5. Potassium cycling and losses in grassland systems : a review

    NARCIS (Netherlands)

    Kayser, M; Isselstein, J

    Cycling of potassium in grassland systems has received relatively little attention in research and practice in recent years. Balanced nutrient systems require consideration of nutrients other than nitrogen (N). Potassium (K) is needed in large amounts and is closely related to N nutrition. In

  6. Mortality hotspots: nitrogen cycling in forest soils during vertebrate decomposition

    Science.gov (United States)

    Decomposing plants and animals fundamentally transform their surrounding environments, and serve as a critical source of limiting nutrients for macro- and micro-fauna. Animal mortality hotspots alter soil biogeochemical cycles, and these natural ephemeral nutrient patches are important for maintaini...

  7. Nutrient management in substrate systems

    NARCIS (Netherlands)

    Sonneveld, C.; Voogt, W.

    2009-01-01

    Speaking about nutrient solutions in soilless cultivation, different solutions can be discerned. Originally, in soilless culture only one nutrient solution was taken into account, being the solution in the containers in which the plants were grown. Such solutions were intensively moved by air

  8. The Nutrient Density of Snacks

    Directory of Open Access Journals (Sweden)

    Julie Hess BA

    2017-03-01

    Full Text Available Background: Although Americans receive almost a quarter of their daily energy from snacks, snacking remains a poorly defined and understood eating occasion. However, there is little dietary guidance about choosing snacks. Families, clinicians, and researchers need a comprehensive approach to assessing their nutritional value. Objective: To quantify and compare the nutrient density of commonly consumed snacks by their overall nutrient profiles using the Nutrient-Rich Foods (NRF Index 10.3. Methods: NRF Index scores were calculated for the top 3 selling products (based on 2014 market research data in different snack categories. These NRF scores were averaged to provide an overall nutrient-density score for each category. Results: Based on NRF scores, yogurt (55.3, milk (52.5, and fruit (30.1 emerged as the most nutrient-dense snacks. Ice cream (−4.4, pies and cakes (−11.1, and carbonated soft drinks (−17.2 emerged as the most nutrient-poor snacks. Conclusions: The NRF Index is a useful tool for assessing the overall nutritional value of snacks based on nutrients to limit and nutrients to encourage.

  9. Nutrient density of beverages in relation to climate impact.

    Science.gov (United States)

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

    2010-08-23

    The food chain contributes to a substantial part of greenhouse gas (GHG) emissions and growing evidence points to the urgent need to reduce GHGs emissions worldwide. Among suggestions were proposals to alter food consumption patterns by replacing animal foods with more plant-based foods. However, the nutritional dimensions of changing consumption patterns to lower GHG emissions still remains relatively unexplored. This study is the first to estimate the composite nutrient density, expressed as percentage of Nordic Nutrition Recommendations (NNR) for 21 essential nutrients, in relation to cost in GHG emissions of the production from a life cycle perspective, expressed in grams of CO(2)-equivalents, using an index called the Nutrient Density to Climate Impact (NDCI) index. The NDCI index was calculated for milk, soft drink, orange juice, beer, wine, bottled carbonated water, soy drink, and oat drink. Due to low-nutrient density, the NDCI index was 0 for carbonated water, soft drink, and beer and below 0.1 for red wine and oat drink. The NDCI index was similar for orange juice (0.28) and soy drink (0.25). Due to a very high-nutrient density, the NDCI index for milk was substantially higher (0.54) than for the other beverages. Future discussion on how changes in food consumption patterns might help avert climate change need to take both GHG emission and nutrient density of foods and beverages into account.

  10. Nutrient density of beverages in relation to climate impact

    Directory of Open Access Journals (Sweden)

    Annika Smedman

    2010-08-01

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

  11. The effect of varying nitrogen and phosphorus availability on nutrient use by Larrea tridentata, a desert evergreen shrub.

    Science.gov (United States)

    Lajtha, Kate; Klein, Melanie

    1988-04-01

    In a phytotron study of the effects of nitrogen and phosphorus supply ratio on nutrient uptake and use by Larrea tridentata, seedlings responded to increases in N and P availability with increases in leaf size, total biomass, and leaf nutrient concentration, and with decreases in root: shoot ratio. N and P use efficiency decreased with increasing N and P availability, respectively, but increased with increasing availability of the other nutrient, suggesting that Larrea responds both to the absolute and to the relative availability of limiting nutrients. Absolute amounts of N and P resorption, as well as N and P resorption efficiencies did not demonstrate a significant trend with nutrient availability, and there was no evidence of significant interactions between the two nutrients. More studies of the effects of nutrient interactions in the cycling and use of nutrients by different plant species are needed before more general conclusions can be drawn.

  12. Soluble iron nutrients in Saharan dust over the central Amazon rainforest

    Science.gov (United States)

    Rizzolo, Joana A.; Barbosa, Cybelli G. G.; Borillo, Guilherme C.; Godoi, Ana F. L.; Souza, Rodrigo A. F.; Andreoli, Rita V.; Manzi, Antônio O.; Sá, Marta O.; Alves, Eliane G.; Pöhlker, Christopher; Angelis, Isabella H.; Ditas, Florian; Saturno, Jorge; Moran-Zuloaga, Daniel; Rizzo, Luciana V.; Rosário, Nilton E.; Pauliquevis, Theotonio; Santos, Rosa M. N.; Yamamoto, Carlos I.; Andreae, Meinrat O.; Artaxo, Paulo; Taylor, Philip E.; Godoi, Ricardo H. M.

    2017-02-01

    The intercontinental transport of aerosols from the Sahara desert plays a significant role in nutrient cycles in the Amazon rainforest, since it carries many types of minerals to these otherwise low-fertility lands. Iron is one of the micronutrients essential for plant growth, and its long-range transport might be an important source for the iron-limited Amazon rainforest. This study assesses the bioavailability of iron Fe(II) and Fe(III) in the particulate matter over the Amazon forest, which was transported from the Sahara desert (for the sake of our discussion, this term also includes the Sahel region). The sampling campaign was carried out above and below the forest canopy at the ATTO site (Amazon Tall Tower Observatory), a near-pristine area in the central Amazon Basin, from March to April 2015. Measurements reached peak concentrations for soluble Fe(III) (48 ng m-3), Fe(II) (16 ng m-3), Na (470 ng m-3), Ca (194 ng m-3), K (65 ng m-3), and Mg (89 ng m-3) during a time period of dust transport from the Sahara, as confirmed by ground-based and satellite remote sensing data and air mass backward trajectories. Dust sampled above the Amazon canopy included primary biological aerosols and other coarse particles up to 12 µm in diameter. Atmospheric transport of weathered Saharan dust, followed by surface deposition, resulted in substantial iron bioavailability across the rainforest canopy. The seasonal deposition of dust, rich in soluble iron, and other minerals is likely to assist both bacteria and fungi within the topsoil and on canopy surfaces, and especially benefit highly bioabsorbent species. In this scenario, Saharan dust can provide essential macronutrients and micronutrients to plant roots, and also directly to plant leaves. The influence of this input on the ecology of the forest canopy and topsoil is discussed, and we argue that this influence would likely be different from that of nutrients from the weathered Amazon bedrock, which otherwise provides the

  13. Advances in the understanding of nutrient dynamics and management in UK agriculture

    International Nuclear Information System (INIS)

    Dungait, Jennifer A.J.; Cardenas, Laura M.; Blackwell, Martin S.A.; Wu, Lianhai; Withers, Paul J.A.; Chadwick, David R.; Bol, Roland; Murray, Philip J.; Macdonald, Andrew J.; Whitmore, Andrew P.; Goulding, Keith W.T.

    2012-01-01

    Current research on macronutrient cycling in UK agricultural systems aims to optimise soil and nutrient management for improved agricultural production and minimise effects on the environment and provision of ecosystem services. Nutrient use inefficiencies can cause environmental pollution through the release of greenhouse gases into the atmosphere and of soluble and particulate forms of N, P and carbon (C) in leachate and run-off into watercourses. Improving nutrient use efficiencies in agriculture calls for the development of sustainable nutrient management strategies: more efficient use of mineral fertilisers, increased recovery and recycling of waste nutrients, and, better exploitation of the substantial inorganic and organic reserves of nutrients in the soil. Long-term field experimentation in the UK has provided key knowledge of the main nutrient transformations in agricultural soils. Emerging analytical technologies, especially stable isotope labelling, that better characterise macronutrient forms and bioavailability and improve the quantification of the complex relationships between the macronutrients in soils at the molecular scale, are augmenting this knowledge by revealing the underlying processes. The challenge for the future is to determine the relationships between the dynamics of N, P and C across scales, which will require both new modelling approaches and integrated approaches to macronutrient cycling. -- Highlights: ► Major advances in the knowledge of macronutrient cycling in agricultural soils are reviewed in the context of management. ► Novel analytical techniques and innovative modelling approaches that enhance understanding of nutrient cycling are explored. ► Knowledge gaps are identified, and the potential to improve comprehension of the integrated nutrient cycles is considered.

  14. Deposition of Boron in Possible Evaporite Deposits in Gale Crate

    Science.gov (United States)

    Gasda, P. J.; Peets, E.; Lamm, S. N.; Rapin, W.; Lanza, N.; Frydenvang, J.; Clark, B. C.; Herkenhoff, K. E.; Bridges, J.; Schwenzer, S. P.; Haldeman, E. B.; Wiens, R. C.; Maurice, S.; Clegg, S. M.; Delapp, D.; Sanford, V.; Bodine, M. R.; McInroy, R.

    2017-12-01

    Boron has been previously detected in Gale crater using the ChemCam instrument on board the NASA Curiosity rover within calcium sulfate fracture fill hosted by lacustrine mudstone and eolian sandstone units. Recent results show that up to 300 ppm B is present in the upper sections of the lacustrine unit. Boron has been detected in both the groundwater-emplaced calcium sulfate fracture fill materials and bedding-parallel calcium sulfate layers. The widespread bedding-parallel calcium sulfate layers within the upper strata of the lacustrine bedrock that Curiosity has encountered recently could be interpreted as primary evaporite deposits. We have two hypotheses for the history of boron in Gale crater. In both hypotheses, borates were first deposited as lake water evaporated, depositing primary evaporates that were later re-dissolved by groundwater, which redistributed the boron into secondary evaporitic calcium sulfate fracture fill deposits. In the first scenario, Gale crater may have undergone a period of perennial lake formation during a drier period of martian history, depositing layers of evaporitic minerals (including borates) among lacustrine mudstone layers. In the second scenario, lake margins could have become periodically exposed during cyclic drops in lake level and subsequently desiccated. Evaporites were deposited and desiccation features were formed in lowstand deposits. Either hypothetical scenario of evaporite deposition would promote prebiotic chemical reactions via wet-dry cycles. Boron may be an important prebiotic element, and as such, its presence in ancient martian surface and groundwater provides evidence that important prebiotic chemical reactions could occur on Mars if organics were present. The presence of boron in ancient Gale crater groundwater also provides additional evidence that a habitable environment existed in the martian subsurface well after the expected disappearance of liquid water on the surface of Mars. We will report on the

  15. Cycle bases to the rescue

    Science.gov (United States)

    Tóbiás, Roland; Furtenbacher, Tibor; Császár, Attila G.

    2017-12-01

    Cycle bases of graph theory are introduced for the analysis of transition data deposited in line-by-line rovibronic spectroscopic databases. The principal advantage of using cycle bases is that outlier transitions -almost always present in spectroscopic databases built from experimental data originating from many different sources- can be detected and identified straightforwardly and automatically. The data available for six water isotopologues, H216O, H217O, H218O, HD16O, HD17O, and HD18O, in the HITRAN2012 and GEISA2015 databases are used to demonstrate the utility of cycle-basis-based outlier-detection approaches. The spectroscopic databases appear to be sufficiently complete so that the great majority of the entries of the minimum cycle basis have the minimum possible length of four. More than 2000 transition conflicts have been identified for the isotopologue H216O in the HITRAN2012 database, the seven common conflict types are discussed. It is recommended to employ cycle bases, and especially a minimum cycle basis, for the analysis of transitions deposited in high-resolution spectroscopic databases.

  16. Daily cycles in coastal dunes

    Science.gov (United States)

    Hunter, R.E.; Richmond, B.M.

    1988-01-01

    Daily cycles of summer sea breezes produce distinctive cyclic foreset deposits in dune sands of the Texas and Oregon coasts. In both areas the winds are strong enough to transport sand only during part of the day, reach a peak during the afternoon, and vary little in direction during the period of sand transport. Cyclicity in the foreset deposits is made evident by variations in the type of sedimentary structure, the texture, and the heavy-mineral content of the sand. Some of the cyclic deposits are made up entirely of one basic type of structure, in which the character of the structure varies cyclically; for example, the angle of climb in a climbing-wind-ripple structure may vary cyclically. Other cyclic deposits are characterized by alternations of two or more structural types. Variations in the concentration of fine-grained heavy minerals, which account for the most striking cyclicity, arise mainly because of segregation on wind-rippled depositional surfaces: where the ripples climb at low angles, the coarsegrained light minerals, which accumulate preferentially on ripple crests, tend to be excluded from the local deposit. Daily cyclic deposits are thickest and best developed on small dunes and are least recognizable near the bases of large dunes. ?? 1988.

  17. Decomposition, nutrient release patterns and nutrient fluxes from ...

    African Journals Online (AJOL)

    Studies were conducted on leaf litter fall, decomposition, nutrient release patterns and nutrient fluxes of Akyaakrom (AS) and Dopiri (DS) secondary forest leaf litter in Dwinyama watershed. Leaf litter production were 9.1 and 6.8 t ha-1 y-1 in AS and 8.9 and 6.5 t ha-1 y-1 in DS in the 1st (September 1998-August 1999) and ...

  18. The biogeochemical iron cycle and astrobiology

    Energy Technology Data Exchange (ETDEWEB)

    Schröder, Christian, E-mail: christian.schroeder@stir.ac.uk [University of Stirling, Biological and Environmental Sciences, School of Natural Sciences (United Kingdom); Köhler, Inga [Eberhard Karls University of Tübingen, Geomicrobiology, Centre for Applied Geoscience (Germany); Muller, Francois L. L. [Qatar University, Department of Biological and Environmental Sciences (Qatar); Chumakov, Aleksandr I.; Kupenko, Ilya; Rüffer, Rudolf [ESRF-The European Synchrotron (France); Kappler, Andreas [Eberhard Karls University of Tübingen, Geomicrobiology, Centre for Applied Geoscience (Germany)

    2016-12-15

    Biogeochemistry investigates chemical cycles which influence or are influenced by biological activity. Astrobiology studies the origin, evolution and distribution of life in the universe. The biogeochemical Fe cycle has controlled major nutrient cycles such as the C cycle throughout geological time. Iron sulfide minerals may have provided energy and surfaces for the first pioneer organisms on Earth. Banded iron formations document the evolution of oxygenic photosynthesis. To assess the potential habitability of planets other than Earth one looks for water, an energy source and a C source. On Mars, for example, Fe minerals have provided evidence for the past presence of liquid water on its surface and would provide a viable energy source. Here we present Mössbauer spectroscopy investigations of Fe and C cycle interactions in both ancient and modern environments. Experiments to simulate the diagenesis of banded iron formations indicate that the formation of ferrous minerals depends on the amount of biomass buried with ferric precursors rather than on the atmospheric composition at the time of deposition. Mössbauer spectra further reveal the mutual stabilisation of Fe-organic matter complexes against mineral transformation and decay of organic matter into CO{sub 2}. This corresponds to observations of a ‘rusty carbon sink’ in modern sediments. The stabilisation of Fe-organic matter complexes may also aid transport of particulate Fe in the water column while having an adverse effect on the bioavailability of Fe. In the modern oxic ocean, Fe is insoluble and particulate Fe represents an important source. Collecting that particulate Fe yields small sample sizes that would pose a challenge for conventional Mössbauer experiments. We demonstrate that the unique properties of the beam used in synchrotron-based Mössbauer applications can be utilized for studying such samples effectively. Reactive Fe species often occur in amorphous or nanoparticulate form in the

  19. The biogeochemical iron cycle and astrobiology

    Science.gov (United States)

    Schröder, Christian; Köhler, Inga; Muller, Francois L. L.; Chumakov, Aleksandr I.; Kupenko, Ilya; Rüffer, Rudolf; Kappler, Andreas

    2016-12-01

    Biogeochemistry investigates chemical cycles which influence or are influenced by biological activity. Astrobiology studies the origin, evolution and distribution of life in the universe. The biogeochemical Fe cycle has controlled major nutrient cycles such as the C cycle throughout geological time. Iron sulfide minerals may have provided energy and surfaces for the first pioneer organisms on Earth. Banded iron formations document the evolution of oxygenic photosynthesis. To assess the potential habitability of planets other than Earth one looks for water, an energy source and a C source. On Mars, for example, Fe minerals have provided evidence for the past presence of liquid water on its surface and would provide a viable energy source. Here we present Mössbauer spectroscopy investigations of Fe and C cycle interactions in both ancient and modern environments. Experiments to simulate the diagenesis of banded iron formations indicate that the formation of ferrous minerals depends on the amount of biomass buried with ferric precursors rather than on the atmospheric composition at the time of deposition. Mössbauer spectra further reveal the mutual stabilisation of Fe-organic matter complexes against mineral transformation and decay of organic matter into CO2. This corresponds to observations of a `rusty carbon sink' in modern sediments. The stabilisation of Fe-organic matter complexes may also aid transport of particulate Fe in the water column while having an adverse effect on the bioavailability of Fe. In the modern oxic ocean, Fe is insoluble and particulate Fe represents an important source. Collecting that particulate Fe yields small sample sizes that would pose a challenge for conventional Mössbauer experiments. We demonstrate that the unique properties of the beam used in synchrotron-based Mössbauer applications can be utilized for studying such samples effectively. Reactive Fe species often occur in amorphous or nanoparticulate form in the environment and

  20. Onset of the aerobic nitrogen cycle during the Great Oxidation Event

    Science.gov (United States)

    Zerkle, Aubrey L.; Poulton, Simon W.; Newton, Robert J.; Mettam, Colin; Claire, Mark W.; Bekker, Andrey; Junium, Christopher K.

    2017-02-01

    The rise of oxygen on the early Earth (about 2.4 billion years ago) caused a reorganization of marine nutrient cycles, including that of nitrogen, which is important for controlling global primary productivity. However, current geochemical records lack the temporal resolution to address the nature and timing of the biogeochemical response to oxygenation directly. Here we couple records of ocean redox chemistry with nitrogen isotope (15N/14N) values from approximately 2.31-billion-year-old shales of the Rooihoogte and Timeball Hill formations in South Africa, deposited during the early stages of the first rise in atmospheric oxygen on the Earth (the Great Oxidation Event). Our data fill a gap of about 400 million years in the temporal 15N/14N record and provide evidence for the emergence of a pervasive aerobic marine nitrogen cycle. The interpretation of our nitrogen isotope data in the context of iron speciation and carbon isotope data suggests biogeochemical cycling across a dynamic redox boundary, with primary productivity fuelled by chemoautotrophic production and a nitrogen cycle dominated by nitrogen loss processes using newly available marine oxidants. This chemostratigraphic trend constrains the onset of widespread nitrate availability associated with ocean oxygenation. The rise of marine nitrate could have allowed for the rapid diversification and proliferation of nitrate-using cyanobacteria and, potentially, eukaryotic phytoplankton.

  1. Onset of the aerobic nitrogen cycle during the Great Oxidation Event.

    Science.gov (United States)

    Zerkle, Aubrey L; Poulton, Simon W; Newton, Robert J; Mettam, Colin; Claire, Mark W; Bekker, Andrey; Junium, Christopher K

    2017-02-23

    The rise of oxygen on the early Earth (about 2.4 billion years ago) caused a reorganization of marine nutrient cycles, including that of nitrogen, which is important for controlling global primary productivity. However, current geochemical records lack the temporal resolution to address the nature and timing of the biogeochemical response to oxygenation directly. Here we couple records of ocean redox chemistry with nitrogen isotope ( 15 N/ 14 N) values from approximately 2.31-billion-year-old shales of the Rooihoogte and Timeball Hill formations in South Africa, deposited during the early stages of the first rise in atmospheric oxygen on the Earth (the Great Oxidation Event). Our data fill a gap of about 400 million years in the temporal 15 N/ 14 N record and provide evidence for the emergence of a pervasive aerobic marine nitrogen cycle. The interpretation of our nitrogen isotope data in the context of iron speciation and carbon isotope data suggests biogeochemical cycling across a dynamic redox boundary, with primary productivity fuelled by chemoautotrophic production and a nitrogen cycle dominated by nitrogen loss processes using newly available marine oxidants. This chemostratigraphic trend constrains the onset of widespread nitrate availability associated with ocean oxygenation. The rise of marine nitrate could have allowed for the rapid diversification and proliferation of nitrate-using cyanobacteria and, potentially, eukaryotic phytoplankton.

  2. Biogeochemical cycling of radionuclides in the environment

    International Nuclear Information System (INIS)

    Livens, F.R.

    1990-01-01

    The biogeochemical cycling of radionuclides with other components such as nutrients around ecosystems is discussed. In particular the behaviour of cesium in freshwater ecosystems since the Chernobyl accident and the behaviour of technetium in the form of pertechnetate anions, TcO 4 , in marine ecosystems is considered. (UK)

  3. Nutrient status and plant growth effects of forest soils in the Basin of Mexico

    Science.gov (United States)

    Mark E. Fenn; V.M. Perea-Estrada; L.I. de Bauer; M. Pérez-Suárez; D.R. Parker; V.M. Cetina-Alcalá

    2006-01-01

    The nutrient status of forest soils in the Mexico City Air Basin was evaluated by observing plant growth responses to fertilization with N, P or both nutrients combined. P deficiency was the most frequent condition for soil from two high pollution sites and N deficiency was greatest at a low N deposition site. Concentrations of Pb and Ni, and to a lesser extent Zn and...

  4. Modelling and mapping of spatial differentiated impacts of nitrogen input to ecosystems within the framework of the UNECE-Convention of Air Pollution Prevention. Part IV. The impact of anthropogenous nitrogen deposition on the diversity and functionality of soil organisms; Modellierung und Kartierung raeumlich differenzierter Wirkungen von Stickstoffeintraegen in Oekosysteme im Rahmen der UNECE-Luftreinhaltekonvention. Teilbericht IV. Der Einfluss anthropogener Stickstoffeintraege auf die Diversitaet und Funktion von Bodenorganismen

    Energy Technology Data Exchange (ETDEWEB)

    Birkhofer, Klaus; Wolters, Volkmar [Giessen Univ. (Germany). Inst. fuer Tieroekologie

    2010-03-15

    Semi-natural ecosystems are exposed to high atmospheric deposition for decades. In contrary to sulphur deposition which could be significantly reduced due to international conventions on air pollution prevention during the last decades, deposition of both, reduced and oxidized nitrogen is still on a very high level in average 40 kg N ha{sup -1} yr{sup -1} in forest ecosystems in Germany. The FuE-Project ''Modelling and mapping of spatial differentiated impacts of nitrogen input to ecosystems within the framework of the UNECE - Convention of Air Pollution Prevention'' was jointly conducted by 4 partner institutions and studied impacts of atmospheric nitrogen deposition and climate change on physicochemical properties of forest soils, nutrient storage and nutrient export (Karlsruhe Research Centre, IMK-IFU) as well as biodiversity of vegetation (OeKO-DATA and Waldkundeinstitut Eberswalde) and soil organisms (Giessen University). Work carried out at Institute of Animal Ecology (Justus Liebig University Giessen) focused on a Meta-Analysis about the impact of N-deposition on the diversity of soil organisms. Based on 1457 relevant publications soil organisms are threatened most in semi-natural ecosystems and experimental increases of nitrogen reduced soil organism diversity in forest ecosystems. Fungi communities were affected most seriously, with a strong decline of diversity in Mycorrhiza communities in response to experimental nitrogen addition. If N-deposition generally affects soil fauna and bacterial communities remains unclear, as the database is either too small or as results are not unequivocal. Those limitations are also present summarizing the impact of N-deposition on functions and services provided by soil organisms, the current literature database does not provide enough results to predict the impact of N-deposition on decomposition processes and nutrient cycling in soils. (orig.)

  5. Monitoring TASCC Injections Using A Field-Ready Wet Chemistry Nutrient Autoanalyzer

    Science.gov (United States)

    Snyder, L. E.; Herstand, M. R.; Bowden, W. B.

    2011-12-01

    Quantification of nutrient cycling and transport (spiraling) in stream systems is a fundamental component of stream ecology. Additions of isotopic tracer and bulk inorganic nutrient to streams have been frequently used to evaluate nutrient transfer between ecosystem compartments and nutrient uptake estimation, respectively. The Tracer Addition for Spiraling Curve Characterization (TASCC) methodology of Covino et al. (2010) instantaneously and simultaneously adds conservative and biologically active tracers to a stream system to quantify nutrient uptake metrics. In this method, comparing the ratio of mass of nutrient and conservative solute recovered in each sample throughout a breakthrough curve to that of the injectate, a distribution of spiraling metrics is calculated across a range of nutrient concentrations. This distribution across concentrations allows for both a robust estimation of ambient spiraling parameters by regression techniques, and comparison with uptake kinetic models. We tested a unique sampling strategy for TASCC injections in which samples were taken manually throughout the nutrient breakthrough curves while, simultaneously, continuously monitoring with a field-ready wet chemistry autoanalyzer. The autoanalyzer was programmed to measure concentrations of nitrate, phosphate and ammonium at the rate of one measurement per second throughout each experiment. Utilization of an autoanalyzer in the field during the experiment results in the return of several thousand additional nutrient data points when compared with manual sampling. This technique, then, allows for a deeper understanding and more statistically robust estimation of stream nutrient spiraling parameters.

  6. Root morphology and mycorrhizal symbioses together shape nutrient foraging strategies of temperate trees.

    Science.gov (United States)

    Chen, Weile; Koide, Roger T; Adams, Thomas S; DeForest, Jared L; Cheng, Lei; Eissenstat, David M

    2016-08-02

    Photosynthesis by leaves and acquisition of water and minerals by roots are required for plant growth, which is a key component of many ecosystem functions. Although the role of leaf functional traits in photosynthesis is generally well understood, the relationship of root functional traits to nutrient uptake is not. In particular, predictions of nutrient acquisition strategies from specific root traits are often vague. Roots of nearly all plants cooperate with mycorrhizal fungi in nutrient acquisition. Most tree species form symbioses with either arbuscular mycorrhizal (AM) or ectomycorrhizal (EM) fungi. Nutrients are distributed heterogeneously in the soil, and nutrient-rich "hotspots" can be a key source for plants. Thus, predicting the foraging strategies that enable mycorrhizal root systems to exploit these hotspots can be critical to the understanding of plant nutrition and ecosystem carbon and nutrient cycling. Here, we show that in 13 sympatric temperate tree species, when nutrient availability is patchy, thinner root species alter their foraging to exploit patches, whereas thicker root species do not. Moreover, there appear to be two distinct pathways by which thinner root tree species enhance foraging in nutrient-rich patches: AM trees produce more roots, whereas EM trees produce more mycorrhizal fungal hyphae. Our results indicate that strategies of nutrient foraging are complementary among tree species with contrasting mycorrhiza types and root morphologies, and that predictable relationships between below-ground traits and nutrient acquisition emerge only when both roots and mycorrhizal fungi are considered together.

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

    Energy Technology Data Exchange (ETDEWEB)

    Rajendran, K.; Devaraj, P. [Institute of Forest Genetics and Tree Breeding, Coimbatore (India)

    2004-03-01

    An experiment was conducted to study the productivity, nutrient distribution and nutrient cycling of Casuarina equisetifolia Forst in farm forestry. Seedlings inoculated with different biofertilizers such as Azospirillum, Phosphobacterium, AM fungi and Frankia along with their combinations were planted in farmland. Growth, biomass, nutrient distribution, nutrient uptake and nutrient-return through litter were estimated 24 months after planting by harvesting the plant. The height of the tree is ranged from 9.87 to 11.90 m and the girth at breast height (gbh) is ranged from 16.8 to 23.2 cm. The maximum height, gbh and total biomass were obtained in the combined application of Azospirillum, Phosphobacterium, AM and Frankia. The combination of AM + Frankia among double inoculation, and in combination of Azospirillum, AM and Frankia in triple inoculation also proved to be the best treatment in promoting the significant total height, gbh and total biomass production. Better nutrient uptake was estimated in combined inoculation of Azospirillum + Phosphobacterium + AM + Frankia followed by Azospirillum + AM + Frankia in respect of the nutrients such as N, P, K, Ca and Mg. The nutrient concentration was distributed in the order of needle > branch > root nodule > twig > stem > root. Nutrient return in field condition showed the maximum nutrient-return through litter in combination with Azospirillum + Phosphobacterium + AM + Frankia inoculated trees. (author)

  8. Root morphology and mycorrhizal symbioses together shape nutrient foraging strategies of temperate trees

    Science.gov (United States)

    Chen, Weile; Koide, Roger T.; Adams, Thomas S.; DeForest, Jared L.; Cheng, Lei; Eissenstat, David M.

    2016-01-01

    Photosynthesis by leaves and acquisition of water and minerals by roots are required for plant growth, which is a key component of many ecosystem functions. Although the role of leaf functional traits in photosynthesis is generally well understood, the relationship of root functional traits to nutrient uptake is not. In particular, predictions of nutrient acquisition strategies from specific root traits are often vague. Roots of nearly all plants cooperate with mycorrhizal fungi in nutrient acquisition. Most tree species form symbioses with either arbuscular mycorrhizal (AM) or ectomycorrhizal (EM) fungi. Nutrients are distributed heterogeneously in the soil, and nutrient-rich “hotspots” can be a key source for plants. Thus, predicting the foraging strategies that enable mycorrhizal root systems to exploit these hotspots can be critical to the understanding of plant nutrition and ecosystem carbon and nutrient cycling. Here, we show that in 13 sympatric temperate tree species, when nutrient availability is patchy, thinner root species alter their foraging to exploit patches, whereas thicker root species do not. Moreover, there appear to be two distinct pathways by which thinner root tree species enhance foraging in nutrient-rich patches: AM trees produce more roots, whereas EM trees produce more mycorrhizal fungal hyphae. Our results indicate that strategies of nutrient foraging are complementary among tree species with contrasting mycorrhiza types and root morphologies, and that predictable relationships between below-ground traits and nutrient acquisition emerge only when both roots and mycorrhizal fungi are considered together. PMID:27432986

  9. Nutrient and Coliform Loading (NCL)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This is a database of available fecal coliform bacteria, fecal streptococci bacteria, and nutrient loading data. Loading for contaminants other than fecal coliform...

  10. Structurally controlled deposition of silicon onto nanowires

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Weijie; Liu, Zuqin; Han, Song; Bornstein, Jonathan; Stefan, Constantin Ionel

    2018-03-20

    Provided herein are nanostructures for lithium ion battery electrodes and methods of fabrication. In some embodiments, a nanostructure template coated with a silicon coating is provided. The silicon coating may include a non-conformal, more porous layer and a conformal, denser layer on the non-conformal, more porous layer. In some embodiments, two different deposition processes, e.g., a PECVD layer to deposit the non-conformal layer and a thermal CVD process to deposit the conformal layer, are used. Anodes including the nanostructures have longer cycle lifetimes than anodes made using either a PECVD or thermal CVD method alone.

  11. Regional scale gradients of climate and nitrogen deposition drive variation in ectomycorrhizal fungal communities associated with native Scots pine.

    Science.gov (United States)

    Jarvis, S; Woodward, S; Alexander, I J; Taylor, A F S

    2013-06-01

    Ectomycorrhizal fungi commonly associate with the roots of forest trees where they enhance nutrient and water uptake, promote seedling establishment and have an important role in forest nutrient cycling. Predicting the response of ectomycorrhizal fungi to environmental change is an important step to maintaining forest productivity in the future. These predictions are currently limited by an incomplete understanding of the relative significance of environmental drivers in determining the community composition of ectomycorrhizal (ECM) fungi at large spatial scales. To identify patterns of community composition in ECM fungi along regional scale gradients of climate and nitrogen deposition in Scotland, fungal communities were analysed from 15 seminatural Scots pine (Pinus sylvestris L.) forests. Fungal taxa were identified by sequencing of the ITS rDNA region using fungal-specific primers. Nonmetric multidimensional scaling was used to assess the significance of 16 climatic, pollutant and edaphic variables on community composition. Vector fitting showed that there was a strong influence of rainfall and soil moisture on community composition at the species level, and a smaller impact of temperature on the abundance of ectomycorrhizal exploration types. Nitrogen deposition was also found to be important in determining community composition, but only when the forest experiencing the highest deposition (9.8 kg N ha(-1)  yr(-1) ) was included in the analysis. This finding supports previously published critical load estimates for ectomycorrhizal fungi of 5-10 kg N ha(-1)  yr(-1) . This work demonstrates that both climate and nitrogen deposition can drive gradients of fungal community composition at a regional scale. © 2013 Blackwell Publishing Ltd.

  12. Biodegradation of hydrocarbons and biogeochemical sulfur cycling in the salt dome environment: Inferences from sulfur isotope and organic geochemical investigations of the Bahloul Formation at the Bou Grine Zn/Pb ore deposit, Tunisia

    Science.gov (United States)

    Bechtel, A.; Shieh, Y.-N.; Pervaz, M.; Püttmann, W.

    1996-08-01

    Combined organic geochemical and stable isotope (S) analyses of samples from the Cretaceous Bahloul Formation (Tunisia) provide insight to oil accumulation processes, biogeochemical alteration of hydrocarbons, microbial sulfate reduction, and mineral deposition at the flanks of the Triassic Jebel Lorbeus diapir, forming the Bou Grine Zn/Pb deposit. The sulfur isotopic composition of the metal sulfides correlates with the degree of biodegradation of hydrocarbons, with the base-metal content and with the proportion of aromatics in the organic extracts. The δ 34S-values are interpreted to reflect bacterial sulfate reduction in a more or less closed system rather than a thermogenic contribution. The extent of H 2S production by the activity of the sulfate-reducing bacteria probably was limited by the availability of sulfate, which in turn was governed by the permeability of the respective sedimentary sequence and by the distance to the anhydrite cap rock. Evidence is provided that biodegradation of hydrocarbons and microbial sulfate reduction contribute to the formation of the high-grade mineralization inside the Bahloul Formation at the contact with the salt dome cap rock. The metals probably were derived through leaching of deeper sedimentary sequences by hot hypersaline basinal brines, evolved by dissolution of salt at the flanks of the diapirs. These hot metalliferous brines are proposed to migrate up around the diapir, finally mixing with near-surface, sulfate-rich brines in the roof zone. When the fluids came in contact with the organic-rich sediments of the Bahloul Formation, the dissolved sulfate was reduced by the sulfate-reducing bacteria. Hydrocarbons generated or accumulated in the Bahloul Formation were utilized by sulfate reducers. The occurrence of high amounts of native sulfur in high-grade ore samples suggest that the production rate of H 2S by bacterial sulfate reduction exceeded its consumption by metal-sulfide precipitation. The supply of dissolved

  13. Happy Cycling

    DEFF Research Database (Denmark)

    Geert Jensen, Birgitte; Nielsen, Tom

    2013-01-01

    og Interaktions Design, Aarhus Universitet under opgave teamet: ”Happy Cycling City – Aarhus”. Udfordringen i studieopgaven var at vise nye attraktive løsningsmuligheder i forhold til cyklens og cyklismens integration i byrum samt at påpege relationen mellem design og overordnede diskussioner af...

  14. Glacial cycles

    DEFF Research Database (Denmark)

    Kaufmann, R. K.; Juselius, Katarina

    We use a statistical model, the cointegrated vector autoregressive model, to assess the degree to which variations in Earth's orbit and endogenous climate dynamics can be used to simulate glacial cycles during the late Quaternary (390 kyr-present). To do so, we estimate models of varying complexi...

  15. CYCLE CONTROL

    African Journals Online (AJOL)

    changed to gestodene. Although large- scale comparative trials are needed to confirm this finding, evidence suggests that cycle control with gestodene is better than for monophasic preparations containing desogestrel, norgestimate or levonorgestrel,10 as well as for levonorg- estrel-or norethisterone-containing triphasics.

  16. Coordination cycles

    Czech Academy of Sciences Publication Activity Database

    Steiner, Jakub

    2008-01-01

    Roč. 63, č. 1 (2008), s. 308-327 ISSN 0899-8256 Institutional research plan: CEZ:AV0Z70850503 Keywords : global games * coordination * crises * cycles and fluctuations Subject RIV: AH - Economics Impact factor: 1.333, year: 2008

  17. Coordination cycles

    Czech Academy of Sciences Publication Activity Database

    Steiner, Jakub

    -, č. 274 (2005), s. 1-26 ISSN 1211-3298 Institutional research plan: CEZ:AV0Z70850503 Keywords : coordination * crises * cycles and fluctuations Subject RIV: AH - Economics http://www.cerge-ei.cz/pdf/wp/Wp274.pdf

  18. Nutrient ratios as a tracer and driver of ocean biogeochemistry.

    Science.gov (United States)

    Deutsch, Curtis; Weber, Thomas

    2012-01-01

    Microbial life in the ocean contains immense taxonomic and physiological diversity, yet its collective activity yields global cycles of the major biolimiting elements N and P that are tightly linked. Moreover, the availability of N and P in seawater is closely matched to the metabolic demands of "average" plankton, as if plankton composition and the oceanic nutrient reservoirs were mutually influenced. These simple observations have broad implications for the function of nutrient cycles within the Earth system, which can operate either as a biological homeostat that buffers ocean fertility against large changes or as an amplifier of climate perturbations, by alleviating or exacerbating the nutrient limitation of biological productivity and ocean C storage. A mechanistic understanding of these observations and dynamics must draw upon diverse fields, from physiology and evolution to physical oceanography and paleoceanography, and must account for processes spanning a wide range of spatial and temporal scales. Here we summarize this understanding from the perspective of the nutrient distributions themselves and their changes over time. We offer a synthesis view in which ocean circulation communicates the resource constraints of stoichiometrically distinct planktonic biomes across large spatial scales, allowing geochemical constancy to emerge from rich biological diversity.

  19. Sulfur cycling in plays an important role in the development of Ocean Anoxic Events

    Science.gov (United States)

    Gomes, M. L.; Raven, M. R.; Fike, D. A.; Gill, B. C.; Johnston, D. T.

    2017-12-01

    cycling and enhanced organic carbon preservation. Given synchronous changes in similar, globally-distributed depositional environments, this impacted the global biogeochemical cycles of oxygen, carbon, and nutrients in ways that sustained decreased oxygen availability and influenced extinction patterns of marine organisms.

  20. Parasite infection alters nitrogen cycling at the ecosystem scale.

    Science.gov (United States)

    Mischler, John; Johnson, Pieter T J; McKenzie, Valerie J; Townsend, Alan R

    2016-05-01

    Despite growing evidence that parasites often alter nutrient flows through their hosts and can comprise a substantial amount of biomass in many systems, whether endemic parasites influence ecosystem nutrient cycling, and which nutrient pathways may be important, remains conjectural. A framework to evaluate how endemic parasites alter nutrient cycling across varied ecosystems requires an understanding of the following: (i) parasite effects on host nutrient excretion; (ii) ecosystem nutrient limitation; (iii) effects of parasite abundance, host density, host functional role and host excretion rate on nutrient flows; and (iv) how this infection-induced nutrient flux compares to other pools and fluxes. Pathogens that significantly increase the availability of a limiting nutrient within an ecosystem should produce a measurable ecosystem-scale response. Here, we combined field-derived estimates of trematode parasite infections in aquatic snails with measurements of snail excretion and tissue stoichiometry to show that parasites are capable of altering nutrient excretion in their intermediate host snails (dominant grazers). We integrated laboratory measurements of host nitrogen excretion with field-based estimates of infection in an ecosystem model and compared these fluxes to other pools and fluxes of nitrogen as measured in the field. Eighteen nitrogen-limited ponds were examined to determine whether infection had a measurable effect on ecosystem-scale nitrogen cycling. Because of their low nitrogen content and high demand for host carbon, parasites accelerated the rate at which infected hosts excreted nitrogen to the water column in a dose-response manner, thereby shifting nutrient stoichiometry and availability at the ecosystem scale. Infection-enhanced fluxes of dissolved inorganic nitrogen were similar to other commonly important environmental sources of bioavailable nitrogen to the system. Additional field measurements within nitrogen-limited ponds indicated that

  1. Shedding of ash deposits

    DEFF Research Database (Denmark)

    Zbogar, Ana; Frandsen, Flemming; Jensen, Peter Arendt

    2009-01-01

    . Deposit shedding can be defined as the process of deposit removal from the heat transfer surfaces. Mechanical and thermal shock devices for deposit removal can be implemented within into the boiler, which can be then referred to as artificial shedding. Sootblowing is one such process, where a pressurized...... on the ash characteristics and the boiler operation. Different deposit characteristics will govern the ash deposit behaviour, and thus the mechanism of deposit shedding. The deposit strength will influence the erosion and gravity shedding mechanisms. The ash viscosity and the melting behaviour will govern...

  2. How to Determine Energy of Wood from Nutrient Analysis?

    OpenAIRE

    Bilot , Nicolas; Saint Andre , Laurent ,; Rogaume , Yann; Fournier , Meriem; Dupont , Capucine; Deleuze , Christine

    2014-01-01

    International audience; In the context of increasing energy demand, forest timber residues and leaves are a potential resource for fuel. How renewable are these resources? What are their qualities as a fuel? These issues can be answered through parallel works in two research fields: forest sciences considering nutrients cycles between plants and soil and growth and yield dynamics of the trees, and energy sciences considering the qualities of fuel such as heating value, and ash content. This i...

  3. Precipitation controls on nutrient budgets in subtropical and tropical forests and the implications under changing climate

    Science.gov (United States)

    Chang, Chung-Te; Wang, Lih-Jih; Huang, Chuan, Jr.; Liu, Chiung-Pin; Wang, Chiao-Ping; Lin, Neng-Huei; Wang, Lixin; Lin, Teng-Chiu

    2017-05-01

    Biological, geological and hydrological drivers collectively control forest biogeochemical cycling. However, based on a close examination of recent literature, we argue that the role of hydrological control particularly precipitation on nutrient budgets is significantly underestimated in subtropical and tropical forests, hindering our predictions of future forest nutrient status under a changing climate in these systems. To test this hypothesis, we analyzed two decades of monthly nutrient input and output data in precipitation and streamwater from a subtropical forested watershed in Taiwan, one of the few sites that has long-term nutrient input-output data in the tropics and subtropics. The results showed that monthly input and output of all ions and budgets (output - input) of most ions were positively correlated with precipitation quantity and there was a surprisingly greater net ion export during the wet growing season, indicating strong precipitation control on the nutrient budget. The strong precipitation control is also supported by the divergence of acidic precipitation and near neutral acidity of streamwater, with the former being independent from precipitation quantity but the latter being positively related to precipitation quantity. An additional synthesis of annual precipitation quantity and nutrient budgets of 32 forests across the globe showed a strong correlation between precipitation quantity and nutrient output-input budget, indicating that strong precipitation control is ubiquitous at the global scale and is particularly important in the humid tropical and subtropical forests. Our results imply that climate change could directly affect ecosystem nutrient cycling in the tropics through changes in precipitation pattern and amount.

  4. Phytomass production and nutrient accumulation by green manure species

    Directory of Open Access Journals (Sweden)

    José Carlos Soares Mangaravite

    2014-10-01

    Full Text Available Green manuring is recognized as a viable alternative to improve nutrient cycling in soils. The aim of this study was to evaluate the phytomass production and nutrient accumulation in shoots of the summer green manures jack bean [Canavalia ensiformis (L. DC.], dwarf pigeon pea (Cajanus cajanvar var. Flavus DC., dwarf mucuna [Mucuna deeringiana (Bort Merr] and sunn hemp (Crotalaria juncea L., under nitrogen fertilization and/or inoculation with N-fixing bacteria. A split plot design was arranged with the four Fabaceae species as main plots and nitrogen fertilization (with and without and inoculation with diazotrophic bacteria (with and without as the subplots, in a 2² factorial. The experiment was arranged as a randomized complete block design with four replications. In the conditions of this trial, the sunn hemp had the highest production of shoot phytomass (12.4 Mg ha-1 and nutrient accumulation, while the dwarf mucuna had the lowest production of shoot phytomass (3.9 Mg ha-1 and nutrient accumulation. The results showed no effect of nitrogen fertilization or inoculation with N-fixing bacteria on the production of shoot phytomass and nutrient accumulation, except for inoculation without nitrogen fertilization, resulting in greater P accumulation (p <0.05 in the sunn hemp and greater Zn and Mn accumulation in the dwarf mucuna. These findings indicate that N fertilization or inoculation with N2-fixing bacteria for Fabaceae are low efficiency practices in the edaphoclimatic conditions of this study.

  5. Soil Nutrient Stocks in Sub-Saharan Africa: Modeling Soil Nutrients Using Machine Learning

    Science.gov (United States)

    Cooper, M. W.; Hengl, T.; Shepherd, K.; Heuvelink, G. B. M.

    2017-12-01

    We present the results of our work modeling 15 target soil nutrients at 250 meter resolution across Sub-Saharan Africa. We used a large stack of GIS layers as covariates, including layers on topography, climate, geology, hydrology and land cover. As training data we used ca. 59,000 soil samples harmonized across a number of projects and datasets, and we modeled each nutrient using an ensemble of random forest and gradient boosting algorithms, implemented using the R packages ranger and xgboost. Using cross validation, we determined that significant models can be produced for organic Carbon, total (organic) Nitrogen, total Phosphorus, and extractable Phosphorous, Potassium, Calcium, Magnesium, Sulfur, Sodium, Iron, Manganese, Zinc, Copper, Aluminum and Boron, with an R-square value between 40 and 95%. The main covariates explaining spatial distribution of nutrients were precipitation and land form parameters. However, we were unable to significantly predict Sulfur, Phosphorus and Boron as these could not be correlated with any environmental covariates we used. Although the accuracy of predictions looks promising, our predictions likely suffer from the significant spatial clustering of the sampling locations, as well as a lack of more detailed data on geology and parent material at a continental scale. These results will contribute to targeting agricultural investments and interventions, as well as targeting restoration efforts and estimating yield potential and yield gaps. These results were recently published in the journal Nutrient Cycling in Agroecosystems (DOI: 10.1007/s10705-017-9870-x) and the maps are available for download under the ODC Open Database License.

  6. Phosphate addition enhanced soil inorganic nutrients to a large extent in three tropical forests.

    Science.gov (United States)

    Zhu, Feifei; Lu, Xiankai; Liu, Lei; Mo, Jiangming

    2015-01-21

    Elevated nitrogen (N) deposition may constrain soil phosphorus (P) and base cation availability in tropical forests, for which limited evidence have yet been available. In this study, we reported responses of soil inorganic nutrients to full factorial N and P treatments in three tropical forests different in initial soil N status (N-saturated old-growth forest and two less-N-rich younger forests). Responses of microbial biomass, annual litterfall production and nutrient input were also monitored. Results showed that N treatments decreased soil inorganic nutrients (except N) in all three forests, but the underlying mechanisms varied depending on forests: through inhibition on litter decomposition in the old-growth forest and through Al(3+) replacement of Ca(2+) in the two younger forests. In contrast, besides great elevation in soil available P, P treatments induced 60%, 50%, 26% increases in sum of exchangeable (K(+)+Ca(2+)+Mg(2+)) in the old-growth and the two younger forests, respectively. These positive effects of P were closely related to P-stimulated microbial biomass and litter nutrient input, implying possible stimulation of nutrient return. Our results suggest that N deposition may result in decreases in soil inorganic nutrients (except N) and that P addition can enhance soil inorganic nutrients to support ecosystem processes in these tropical forests.

  7. Geographical Distribution and Sources of Nutrients in Atmospheric Aerosol Over the Pacific Ocean

    Science.gov (United States)

    Uematsu, M.

    2016-12-01

    The Pacific Ocean, the world's largest (occupying about 30% of the Earth's total surface area) has several distinguishing biogeochemical features. In the western Pacific, dust particles originating from arid and semi-arid regions in Asia and Australia are transported to the north and south, respectively. Biomass burning emissions from Southeast Asia are exported to the tropical Pacific, and anthropogenic substances flowing out of Asia and Eurasia spread both regionally and globally. Over high primary productive areas such as the subarctic North Pacific, the equatorial Pacific and the Southern Ocean, biogenic gasses are released to the atmosphere and transported to other areas. These processes may affect cloud and rainfall patterns, air quality, and the radiative balance of downwind regions. The deposition of atmospheric aerosols containing iron and other essential nutrients is important for biogeochemical cycles in the oceans because this source of nutrients helps sustain primary production and affects food-web structure; these effects in turn influence the chemical properties of marine atmosphere. From an atmospheric chemistry standpoint, sea-salt aerosols produced by strong winds and marine biogenic gases emitted from highly productive waters affect the physicochemical characteristics of marine aerosols. As phytoplankton populations are patchy and atmospheric processes sporadic, the interactions between atmospheric chemical constituents and marine biota vary for different regions as well as seasonally and over longer timescales. To address these and other emerging issues, and more generally to better understand the important biogeochemical processes and interactions occurring over the open oceans, more long-term recurrent research cruises with standardized atmospheric shipboard measurements will be needed in the future.

  8. The Stoichiometry of Nutrient Release by Terrestrial Herbivores and Its Ecosystem Consequences

    Directory of Open Access Journals (Sweden)

    Judith Sitters

    2017-04-01

    Full Text Available It is widely recognized that the release of nutrients by herbivores via their waste products strongly impacts nutrient availability for autotrophs. The ratios of nitrogen (N and phosphorus (P recycled through herbivore release (i.e., waste N:P are mainly determined by the stoichiometric composition of the herbivore's food (food N:P and its body nutrient content (body N:P. Waste N:P can in turn impact autotroph nutrient limitation and productivity. Herbivore-driven nutrient recycling based on stoichiometric principles is dominated by theoretical and experimental research in freshwater systems, in particular interactions between algae and invertebrate herbivores. In terrestrial ecosystems, the impact of herbivores on nutrient cycling and availability is often limited to studying carbon (C:N and C:P ratios, while the role of terrestrial herbivores in mediating N:P ratios is also likely to influence herbivore-driven nutrient recycling. In this review, we use rules and predictions on the stoichiometry of nutrient release originating from algal-based aquatic systems to identify the factors that determine the stoichiometry of nutrient release by herbivores. We then explore how these rules can be used to understand the stoichiometry of nutrient release by terrestrial herbivores, ranging from invertebrates to mammals, and its impact on plant nutrient limitation and productivity. Future studies should focus on measuring both N and P when investigating herbivore-driven nutrient recycling in terrestrial ecosystems, while also taking the form of waste product (urine or feces and other pathways by which herbivores change nutrients into account, to be able to quantify the impact of waste stoichiometry on plant communities.

  9. The stoichiometry of nutrient release by terrestrial herbivores and its ecosystem consequences

    Science.gov (United States)

    Sitters, Judith; Bakker, Elisabeth S.; Veldhuis, Michiel P.; Veen, G. F.; Olde Venterink, Harry; Vanni, Michael J.

    2017-04-01

    It is widely recognized that the release of nutrients by herbivores via their waste products strongly impacts nutrient availability for autotrophs. The ratios of nitrogen (N) and phosphorus (P) recycled through herbivore release (i.e., waste N:P) are mainly determined by the stoichiometric composition of the herbivore’s food (food N:P) and its body nutrient content (body N:P). Waste N:P can in turn impact autotroph nutrient limitation and productivity. Herbivore-driven nutrient recycling based on stoichiometric principles is dominated by theoretical and experimental research in freshwater systems, in particular interactions between algae and invertebrate herbivores. In terrestrial ecosystems, the impact of herbivores on nutrient cycling and availability is often limited to studying carbon (C ):N and C:P ratios, while the role of terrestrial herbivores in mediating N:P ratios is also likely to influence herbivore-driven nutrient recycling. In this review, we use rules and predictions on the stoichiometry of nutrient release originating from algal-based aquatic systems to identify the factors that determine the stoichiometry of nutrient release by herbivores. We then explore how these rules can be used to understand the stoichiometry of nutrient release by terrestrial herbivores, ranging from invertebrates to mammals, and its impact on plant nutrient limitation and productivity. Future studies should focus on measuring both N and P when investigating herbivore-driven nutrient recycling in terrestrial ecosystems, while also taking the form of waste product (urine or feces) and other pathways by which herbivores change nutrients into account, to be able to quantify the impact of waste stoichiometry on plant communities.

  10. Watch: Current knowledge of the terrestrial Global Water Cycle"

    NARCIS (Netherlands)

    Harding, R.; Best, M.; Hagemann, S.; Kabat, P.; Tallaksen, L.M.; Warnaars, T.; Wiberg, D.; Weedon, G.P.; Lanen, van H.A.J.; Ludwig, F.; Haddeland, I.

    2011-01-01

    Water-related impacts are among the most important consequences of increasing greenhouse gas concentrations. Changes in the global water cycle will also impact the carbon and nutrient cycles and vegetation patterns. There is already some evidence of increasing severity of floods and droughts and

  11. Epiphytic bryophytes as bio-indicators of atmospheric nitrogen deposition in a subtropical montane cloud forest: Response patterns, mechanism, and critical load.

    Science.gov (United States)

    Shi, Xian-Meng; Song, Liang; Liu, Wen-Yao; Lu, Hua-Zheng; Qi, Jin-Hua; Li, Su; Chen, Xi; Wu, Jia-Fu; Liu, Shuai; Wu, Chuan-Sheng

    2017-10-01

    Increasing trends of atmospheric nitrogen (N) deposition due to pollution and land-use changes are dramatically altering global biogeochemical cycles. Bryophytes, which are extremely vulnerable to N deposition, often play essential roles in these cycles by contributing to large nutrient pools in boreal and montane forest ecosystems. To interpret the sensitivity of epiphytic bryophytes for N deposition and to determine their critical load (CL) in a subtropical montane cloud forest, community-level, physiological and chemical responses of epiphytic bryophytes were tested in a 2-year field experiment of N additions. The results showed a significant decrease in the cover of the bryophyte communities at an N addition level of 7.4 kg ha -1 yr -1 , which is consistent with declines in the biomass production, vitality, and net photosynthetic rate responses of two dominant bryophyte species. Given the background N deposition rate of 10.5 kg ha -1 yr -1 for the study site, a CL of N deposition is therefore estimated as ca. 18 kg N ha -1 yr -1 . A disordered cellular carbon (C) metabolism, including photosynthesis inhibition and ensuing chlorophyll degradation, due to the leakage of magnesium and potassium and corresponding downstream effects, along with direct toxic effects of excessive N additions is suggested as the main mechanism driving the decline of epiphytic bryophytes. Our results confirmed the process of C metabolism and the chemical stability of epiphytic bryophytes are strongly influenced by N addition levels; when coupled to the strong correlations found with the loss of bryophytes, this study provides important and timely evidence on the response mechanisms of bryophytes in an increasingly N-polluted world. In addition, this study underlines a general decline in community heterogeneity and biomass production of epiphytic bryophytes induced by increasing N deposition. Copyright © 2017 Elsevier Ltd. All rights reserved.

  12. Comparing the Life Cycle Energy Consumption, Global ...

    Science.gov (United States)

    Managing the water-energy-nutrient nexus for the built environment requires, in part, a full system analysis of energy consumption, global warming and eutrophication potentials of municipal water services. As an example, we evaluated the life cycle energy use, greenhouse gas (GHG) emissions and aqueous nutrient releases of the whole anthropogenic municipal water cycle starting from raw water extraction to wastewater treatment and reuse/discharge for five municipal water and wastewater systems. The assessed options included conventional centralized services and four alternative options following the principles of source-separation and water fit-for-purpose. The comparative life cycle assessment identified that centralized drinking water supply coupled with blackwater energy recovery and on-site greywater treatment and reuse was the most energyand carbon-efficient water service system evaluated, while the conventional (drinking water and sewerage) centralized system ranked as the most energy- and carbon-intensive system. The electricity generated from blackwater and food residuals co-digestion was estimated to offset at least 40% of life cycle energy consumption for water/waste services. The dry composting toilet option demonstrated the lowest life cycle eutrophication potential. The nutrients in wastewater effluent are the dominating contributors for the eutrophication potential for the assessed system configurations. Among the parameters for which variability

  13. Fuel cycle

    International Nuclear Information System (INIS)

    Bahm, W.

    1989-01-01

    The situation of the nuclear fuel cycle for LWR type reactors in France and in the Federal Republic of Germany was presented in 14 lectures with the aim to compare the state-of-the-art in both countries. In addition to the momentarily changing fuilds of fuel element development and fueling strategies, the situation of reprocessing, made interesting by some recent developmnts, was portrayed and differences in ultimate waste disposal elucidated. (orig.) [de

  14. Atmospheric deposition fluxes to Monetary Bay

    Science.gov (United States)

    Gray, E.; Paytan, A.; Ryan, J.

    2008-12-01

    Atmospheric deposition has been widely recognized as a source of pollutants and nutrients to coastal ecosystems. Specifically, deposition includes nitrogen compounds, sulfur compounds, mercury, pesticides, phosphate, trace metals and other toxic compounds that can travel great distances. Sources of these components include both natural (volcanoes, mineral dust, forest fires) and anthropogenic (fossil fuels, chemical byproducts, incineration of waste) sources, which may contribute to harmful health and environmental impacts such as eutrophication, contaminated fish and harmful algal blooms. This study looks at the flux of aerosol deposition (TSP - total suspended particle load) to Monterey Bay, California. Samples are collected on a cascade impactor aerosol sampler (size fractions PM 2.5 and PM 10) every 48 hours continuously. Preliminary results indicate that the TSP for PM 10 ranged from 0.026 to 0.104 mg m-3 of air and for PM 2.5 from 0.014 to 0.046 mg m-3 of air. Using a deposition velocity of 2 cm s-1 for the large fraction (PM10 - PM 2.5) and a deposition velocity of 0.7 cm s-1 for the fine fraction (PM 2.5) deposition rates are 13 and 86 mg m-2 d-1 respectively.

  15. Imbalanced nutrients as triggers for black shale formation in a shallow shelf setting during the OAE 2 (Wunstorf, Germany

    Directory of Open Access Journals (Sweden)

    M. Blumenberg

    2012-10-01

    Full Text Available During the oceanic anoxic event 2 (OAE 2 in the Mid-Cretaceous Period, widespread black shale (BS formation occurred, reflecting perturbations in major biogeochemical cycles. Here we present geochemical and biomarker data of the OAE 2 from a shelf setting situated at about 100–150 m water depth (Wunstorf, Germany. Our data support that processes inducing BS deposition were related to orbital cyclicity in Wunstorf and that they were not restricted to the time of the OAE 2 carbon isotope excursion. Correlations of total organic carbon (TOC and δ15N and high relative abundances of functionalized hopanoids (including 2-methylated structures suggest that BS were formed during times of imbalanced nutrients with high phosphorus inputs and increased cyanobacterial nitrogen fixation. Periods of BS formation were also characterized by enhanced growth of dinoflagellates and bacteriovorous ciliates, the latter supporting the presence of a stratified water body. The lack of biomarkers specific for green sulfur bacteria excludes photic zone euxinia during OAE 2 in Wunstorf. Conflicting maturities and biomarker distributions in kerogen and extractable organic matter and, interestingly, a negative correlation of the diagenetically resistant 2-methyl hopane hydrocarbons with TOC indicate a complex depositional setting at Wunstorf. This might have been induced by high continental runoff during BS formation and the accompanying mobilisation of refractory OM from the shelves and near shore areas.

  16. Nutrient acquisition strategies of mammalian cells.

    Science.gov (United States)

    Palm, Wilhelm; Thompson, Craig B

    2017-06-07

    Mammalian cells are surrounded by diverse nutrients, such as glucose, amino acids, various macromolecules and micronutrients, which they can import through transmembrane transporters and endolysosomal pathways. By using different nutrient sources, cells gain metabolic flexibility to survive periods of starvation. Quiescent cells take up sufficient nutrients to sustain homeostasis. However, proliferating cells depend on growth-factor-induced increases in nutrient uptake to support biomass formation. Here, we review cellular nutrient acquisition strategies and their regulation by growth factors and cell-intrinsic nutrient sensors. We also discuss how oncogenes and tumour suppressors promote nutrient uptake and thereby support the survival and growth of cancer cells.

  17. TOR Signaling and Nutrient Sensing.

    Science.gov (United States)

    Dobrenel, Thomas; Caldana, Camila; Hanson, Johannes; Robaglia, Christophe; Vincentz, Michel; Veit, Bruce; Meyer, Christian

    2016-04-29

    All living organisms rely on nutrients to sustain cell metabolism and energy production, which in turn need to be adjusted based on available resources. The evolutionarily conserved target of rapamycin (TOR) protein kinase is a central regulatory hub that connects environmental information about the quantity and quality of nutrients to developmental and metabolic processes in order to maintain cellular homeostasis. TOR is activated by both nitrogen and carbon metabolites and promotes energy-consuming processes such as cell division, mRNA translation, and anabolism in times of abundance while repressing nutrient remobilization through autophagy. In animals and yeasts, TOR acts antagonistically to the starvation-induced AMP-activated kinase (AMPK)/sucrose nonfermenting 1 (Snf1) kinase, called Snf1-related kinase 1 (SnRK1) in plants. This review summarizes the immense knowledge on the relationship between TOR signaling and nutrients in nonphotosynthetic organisms and presents recent findings in plants that illuminate the crucial role of this pathway in conveying nutrient-derived signals and regulating many aspects of metabolism and growth.

  18. Nutrient canal of the fibula

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Joo-Hyuk; Ehara, Shigeru; Tamakawa, Yoshiharu [Departments of Radiology, Iwate Medical University School of Medicine, Morioka (Japan); Horiguchi, Masahura [Department of Anatomy I, Iwate Medical University School of Medicine, Morioka (Japan)

    2000-01-01

    Objective. To investigate the radiological features of the nutrient canal in the fibula.Design and patients. One hundred and seventy-nine dried fibulae were studied regarding the type, number, location, and direction of the nutrient canal. They were classified into a usual type (type I: a radiolucent line confined to the cortex) and an atypical type (type II: a radiolucent line extending beyond the cortex).Results. Among the total of 230 nutrient canals seen on radiography, 197 (86%) were type I and 33 (14%) were type II. On CT scans, the ossified rim of the canal extended into the medullary cavity in type II canals. The most common site was the posteromedial aspect in both type I and type II canals. Type II canals were significantly more common in fibulae with two or three nutrient canals. The frequency of the upward direction was more common in type II canals.Conclusion. Nutrient canals with extension of the ossified rim into the medullary canal are the cause of linear lucency that may simulate a fracture. Their features are slightly different from those of usual canals. (orig.)

  19. Nutrient limitation in tropical secondary forests following different management practices.

    Science.gov (United States)

    Nagy, R Chelsea; Rastetter, Edward B; Neill, Christopher; Porder, Stephen

    2017-04-01

    Secondary forests now make up more than one-half of all tropical forests, and constraints on their biomass accumulation will influence the strength of the terrestrial carbon (C) sink in the coming decades. However the variance in secondary tropical forest biomass for a given stand age and climate is high and our understanding of why is limited. We constructed a model of terrestrial C, nitrogen (N), and phosphorus (P) cycling to examine the influence of disturbance and management practices on nutrient limitation and biomass recovery in secondary tropical forests. The model predicted that N limited the rate of forest recovery in the first few decades following harvest, but that this limitation switched to P approximately 30-40 yr after abandonment, consistent with field data on N and P cycling from secondary tropical forest chronosequences. Simulated biomass recovery agreed well with field data of biomass accumulation following harvest (R 2  = 0.80). Model results showed that if all biomass remained on site following a severe disturbance such as blowdown, regrowth approached pre-disturbance biomass in 80-90 yr, and recovery was faster following smaller disturbances such as selective logging. Field data from regrowth on abandoned pastures were consistent with simulated losses of nutrients in soil organic matter, particularly P. Following any forest disturbance that involved the removal of nutrients (i.e., except blowdown), forest regrowth produced reduced biomass relative to the initial state as a result of nutrient loss through harvest, leaching and/or sequestration by secondary minerals. Differences in nutrient availability accounted for 49-94% of the variance in secondary forest biomass C at a given stand age. Management lessons from this study are the importance of strategies that help retain nutrients on site, recognizing the role of coarse woody debris in immobilization and subsequent release of nutrients, and the potential for nutrient additions to enhance

  20. Nutrient vectors and riparian nutrient processing in African semiarid savanna ecosystems

    Science.gov (United States)

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

    2007-01-01

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

  1. Nutrient supply of plants in aquaponic systems

    OpenAIRE

    Andras Bittsanszky; Nikolett Uzinger; Gábor Gyulai; Alex Mathis; Ranka Junge; Morris Villarroel; Benzion Kotzen; Tamas Komives

    2016-01-01

    In this preliminary article we present data on plant nutrient concentrations in aquaponic systems, and compare them to nutrient concentrations in “standard” hydroponic solutions. Our data shows that the nutrient concentrations supplied by the fish in aquaponic system are significantly lower for most nutrients, compared to hydroponic systems. Nevertheless, plants do thrive in solutions that have lower nutrient levels than “standard” hydroponic solutions. This is especially true for green leafy...

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

    Digital Repository Service at National Institute of Oceanography (India)

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

    are gaining considerable attention due to their potential impact on biogeochemistry of ocean surface (Duce, 1986; 1991; 2008; Jickells et al., 2005; Mahowald et al., 2011; Prospero et al., 2009). A significant increase in the eutrophication caused... by atmospheric deposition of reactive nitrogen (Paerl et al., 2002; Paerl and Whitall, 1999) further emphasizes the need to assess the impact of air-sea deposition of nutrients to oceanic regions. The increasingly growing use of fertilizers, emissions from...

  3. Plants cause ecosystem nutrient depletion via the interruption of bird-derived spatial subsidies

    Science.gov (United States)

    Young, Hillary S.; McCauley, Douglas J.; Dunbar, Robert B.; Dirzo, Rodolfo

    2010-01-01

    Plant introductions and subsequent community shifts are known to affect nutrient cycling, but most such studies have focused on nutrient enrichment effects. The nature of plant-driven nutrient depletions and the mechanisms by which these might occur are relatively poorly understood. In this study we demonstrate that the proliferation of the commonly introduced coconut palm, Cocos nucifera, interrupts the flow of allochthonous marine subsidies to terrestrial ecosystems via an indirect effect: impact on birds. Birds avoid nesting or roosting in C. nucifera, thus reducing the critical nutrient inputs they bring from the marine environment. These decreases in marine subsidies then lead to reductions in available soil nutrients, decreases in leaf nutrient quality, diminished leaf palatability, and reduced herbivory. This nutrient depletion pathway contrasts the more typical patterns of nutrient enrichment that follow plant species introductions. Research on the effects of spatial subsidy disruptions on ecosystems has not yet examined interruptions driven by changes within the recipient community, such as plant community shifts. The ubiquity of coconut palm introductions across the tropics and subtropics makes these observations particularly noteworthy. Equally important, the case of C. nucifera provides a strong demonstration of how plant community changes can dramatically impact the supply of allochthonous nutrients and thereby reshape energy flow in ecosystems. PMID:20133852

  4. Nutrient Limitation of Microbial Mediated Decomposition and Arctic Soil Chronology

    Science.gov (United States)

    Melle, C. J.; Darrouzet-Nardi, A.; Wallenstein, M. D.

    2012-12-01

    Soils of northern permafrost regions currently contain twice as much carbon as the entire Earth's atmosphere. Traditionally, environmental constraints have limited microbial activity resulting in restricted decomposition of soil organic matter in these systems and accumulation of massive amounts of soil organic carbon (SOC), however climate change is reducing the constraints of decomposition in arctic permafrost regions. Carbon cycling in nutrient poor, arctic ecosystems is tightly coupled to other biogeochemical cycles. Several studies have suggested strong nitrogen limitations of primary productivity and potentially warm-season microbial activity in these nutrient deficient soils. Nitrogen is required for microbial extracellular enzyme production which drives the decomposition of soil organic matter (SOM). Nitrogen limited arctic soils may also experience limitation via labile carbon availability despite the SOM rich environment due to low extracellular enzyme production. Few studies have directly addressed nutrient induced microbial limitation in SOC rich arctic tundra soils, and even less is known about the potential for nutrient co-limitation. Additionally, through the process of becoming deglaciated, sites within close proximity to one another may have experienced drastic differences in their effective soil ages due to the varied length of their active histories. Many soil properties and nutrient deficiencies are directly related to soil age, however this chronology has not previously been a focus of research on nutrient limitation of arctic soil microbial activity. Understanding of nutrient limitations, as well as potential co-limitation, on arctic soil microbial activity has important implications for carbon cycling and the ultimate fate of the current arctic SOC reservoir. Analyses of nutrient limitation on soils of a single site are not adequate for fully understanding the controls on soil microbial activity across a vast land mass with large variation in

  5. Soil nutrient availability and reproductive effort drive patterns in nutrient resorption in Pentachlethra macroloba

    Science.gov (United States)

    K. L. Tully; Tana Wood; A. M. Schwantes; D. Lawrence

    2013-01-01

    The removal of nutrients from senescing tissues, nutrient resorption, is a key strategy for conserving nutrients in plants. However, our understanding of what drives patterns of nutrient resorption in tropical trees is limited. We examined the effects of nutrient sources (stand-level and tree-level soil fertility) and sinks (reproductive effort) on nitrogen (N) and...

  6. Nonlinear Interactions between Climate and Atmospheric Carbon Dioxide Drivers of Terrestrial and Marine Carbon Cycle Changes

    Science.gov (United States)

    Hoffman, F. M.; Randerson, J. T.; Moore, J. K.; Goulden, M.; Fu, W.; Koven, C.; Swann, A. L. S.; Mahowald, N. M.; Lindsay, K. T.; Munoz, E.

    2017-12-01

    Quantifying interactions between global biogeochemical cycles and the Earth system is important for predicting future atmospheric composition and informing energy policy. We applied a feedback analysis framework to three sets of Historical (1850-2005), Representative Concentration Pathway 8.5 (2006-2100), and its extension (2101-2300) simulations from the Community Earth System Model version 1.0 (CESM1(BGC)) to quantify drivers of terrestrial and ocean responses of carbon uptake. In the biogeochemically coupled simulation (BGC), the effects of CO2 fertilization and nitrogen deposition influenced marine and terrestrial carbon cycling. In the radiatively coupled simulation (RAD), the effects of rising temperature and circulation changes due to radiative forcing from CO2, other greenhouse gases, and aerosols were the sole drivers of carbon cycle changes. In the third, fully coupled simulation (FC), both the biogeochemical and radiative coupling effects acted simultaneously. We found that climate-carbon sensitivities derived from RAD simulations produced a net ocean carbon storage climate sensitivity that was weaker and a net land carbon storage climate sensitivity that was stronger than those diagnosed from the FC and BGC simulations. For the ocean, this nonlinearity was associated with warming-induced weakening of ocean circulation and mixing that limited exchange of dissolved inorganic carbon between surface and deeper water masses. For the land, this nonlinearity was associated with strong gains in gross primary production in the FC simulation, driven by enhancements in the hydrological cycle and increased nutrient availability. We developed and applied a nonlinearity metric to rank model responses and driver variables. The climate-carbon cycle feedback gain at 2300 was 42% higher when estimated from climate-carbon sensitivities derived from the difference between FC and BGC than when derived from RAD. We re-analyzed other CMIP5 model results to quantify the

  7. Microbial extracellular enzymes in biogeochemical cycling of ecosystems.

    Science.gov (United States)

    Luo, Ling; Meng, Han; Gu, Ji-Dong

    2017-07-15

    Extracellular enzymes, primarily produced by microorganisms, affect ecosystem processes because of their essential roles in degradation, transformation and mineralization of organic matter. Extracellular enzymes involved in the cycling of carbon (C), nitrogen (N) and phosphorus (P) have been widely investigated in many different ecosystems, and several enzymes have been recognized as key components in regulating C storage and nutrient cycling. In this review, it was the first time to summarize the specific extracellular enzymes related to C storage and nutrient cycling for better understanding the important role of microbial extracellular enzymes in biogeochemical cycling of ecosystems. Subsequently, ecoenzymatic stoichiometry - the relative ratio of extracellular enzyme, has been reviewed and further provided a new perspective for understanding biogeochemical cycling of ecosystems. Finally, the new insights of using microbial extracellular enzyme in indicating biogeochemical cycling and then protecting ecosystems have been suggested. Copyright © 2017 Elsevier Ltd. All rights reserved.

  8. Happy Cycling

    DEFF Research Database (Denmark)

    Geert Jensen, Birgitte; Nielsen, Tom

    2013-01-01

    Artiklens formål er at diskutere oplevede kvaliteter og adfærdsaspekter af mobilitet med udgangspunkt i spørgsmålet om cykling i byer og relationen mellem design og adfærd. Artiklen tager afsæt i et studie forløb der involverede studerende fra Urban Design, Industriel Design Arkitektskolen Aarhus...... og Interaktions Design, Aarhus Universitet under opgave teamet: ”Happy Cycling City – Aarhus”. Udfordringen i studieopgaven var at vise nye attraktive løsningsmuligheder i forhold til cyklens og cyklismens integration i byrum samt at påpege relationen mellem design og overordnede diskussioner af...

  9. Nutrient-enhancement of Matooke banana for improved nutrient ...

    African Journals Online (AJOL)

    A total of 173 PLHIVregistered with Rakai Health Science Project were chosen and interviewed using structured questionnaires to determine the current contribution of banana to the household food security. Nutrient intake data were collected using Gibson s 24-hour recall method and food frequency questionnaires.

  10. Effect of Processing Methods on the Nutrients and Anti Nutrients ...

    African Journals Online (AJOL)

    appropriate methods for retaining its nutrients and reducing to a moderate level, its antinutrients compositions. The leaves were subjected to different processing methods such as boiling for 3mins at 100oC, blanching at 62oC for 5mins, squeeze-washing with 250ml of clean water for 3 rounds each lasting 3mins, a combine ...

  11. Scaling Dissolved Nutrient Removal in River Networks: A Comparative Modeling Investigation

    Science.gov (United States)

    Ye, Sheng; Reisinger, Alexander J.; Tank, Jennifer L.; Baker, Michelle A.; Hall, Robert O.; Rosi, Emma J.; Sivapalan, Murugesu

    2017-11-01

    Along the river network, water, sediment, and nutrients are transported, cycled, and altered by coupled hydrological and biogeochemical processes. Our current understanding of the rates and processes controlling the cycling and removal of dissolved inorganic nutrients in river networks is limited due to a lack of empirical measurements in large, (nonwadeable), rivers. The goal of this paper was to develop a coupled hydrological and biogeochemical process model to simulate nutrient uptake at the network scale during summer base flow conditions. The model was parameterized with literature values from headwater streams, and empirical measurements made in 15 rivers with varying hydrological, biological, and topographic characteristics, to simulate nutrient uptake at the network scale. We applied the coupled model to 15 catchments describing patterns in uptake for three different solutes to determine the role of rivers in network-scale nutrient cycling. Model simulation results, constrained by empirical data, suggested that rivers contributed proportionally more to nutrient removal than headwater streams given the fraction of their length represented in a network. In addition, variability of nutrient removal patterns among catchments was varied among solutes, and as expected, was influenced by nutrient concentration and discharge. Net ammonium uptake was not significantly correlated with any environmental descriptor. In contrast, net daily nitrate removal was linked to suspended chlorophyll a (an indicator of primary producers) and land use characteristics. Finally, suspended sediment characteristics and agricultural land use were correlated with net daily removal of soluble reactive phosphorus, likely reflecting abiotic sorption dynamics. Rivers are understudied relative to streams, and our model suggests that rivers can contribute more to network-scale nutrient removal than would be expected based upon their representative fraction of network channel length.

  12. A seasonal nitrogen deposition budget for Rocky Mountain National Park.

    Science.gov (United States)

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

    2013-07-01

    deposition of organic nitrogen and dry deposition of ammonia; combined they contributed 1.37 kg N x ha(-1)yr(-1) or 37% of the total nitrogen deposition budget. To better understand the nitrogen cycle and key interactions between the atmosphere and biosphere we need to include as many sources and types of nitrogen as possible and understand their variability throughout the year. Here we examine the components of the nitrogen deposition budget to better understand the factors that influence the different deposition pathways and their seasonal variations.

  13. The duration of mitosis and daughter cell size are modulated by nutrients in budding yeast.

    Science.gov (United States)

    Leitao, Ricardo M; Kellogg, Douglas R

    2017-11-06

    The size of nearly all cells is modulated by nutrients. Thus, cells growing in poor nutrients can be nearly half the size of cells in rich nutrients. In budding yeast, cell size is thought to be controlled almost entirely by a mechanism that delays cell cycle entry until sufficient growth has occurred in G1 phase. Here, we show that most growth of a new daughter cell occurs in mitosis. When the rate of growth is slowed by poor nutrients, the duration of mitosis is increased, which suggests that cells compensate for slow growth in mitosis by increasing the duration of growth. The amount of growth required to complete mitosis is reduced in poor nutrients, leading to a large reduction in cell size. Together, these observations suggest that mechanisms that control the extent of growth in mitosis play a major role in cell size control in budding yeast. © 2017 Leitao and Kellogg.

  14. SEM and XPS study of layer-by-layer deposited polypyrrole thin films

    Science.gov (United States)

    Pigois-Landureau, E.; Nicolau, Y. F.; Delamar, M.

    1996-01-01

    Layer-by-layer deposition of thin films (a few nm) of polypyrrole was carried out on various substrates such as silver, platinum, electrochemically oxidized aluminum and pretreated glass. SEM micrographs showed that the deposited layers nucleate by an island-type mechanism on hydrated alumina and KOH-pretreated (hydrophilic) glass before forming a continuous film. However, continuous thin films are obtained on chromic acid pretreated (hydrophobic) glass and sputtered Ag or Pt on glass after only 3-4 deposition cycles. The mean deposition rate evaluated by XPS for the first deposition cycles on Ag and Pt is 3 and 4 nm/cycle, respectively, in agreement with previous gravimetric determinations on thicker films, proving the constancy of the deposition rate. The XPS study of the very thin films obtained by a few deposition cycles shows that the first polypyrrole layers are dedoped by hydroxydic (basic) substrate surfaces.

  15. SEM and XPS study of layer-by-layer deposited polypyrrole thin films

    International Nuclear Information System (INIS)

    Pigois-Landureau, E.; Nicolau, Y.F.; Delamar, M.

    1996-01-01

    Layer-by-layer deposition of thin films (a few nm) of polypyrrole was carried out on various substrates such as silver, platinum, electrochemically oxidized aluminum and pretreated glass. SEM micrographs showed that the deposited layers nucleate by an island-type mechanism on hydrated alumina and KOH-pretreated (hydrophilic) glass before forming a continuous film. However, continuous thin films are obtained on chromic acid pretreated (hydrophobic) glass and sputtered Ag or Pt on glass after only 3 endash 4 deposition cycles. The mean deposition rate evaluated by XPS for the first deposition cycles on Ag and Pt is 3 and 4 nm/cycle, respectively, in agreement with previous gravimetric determinations on thicker films, proving the constancy of the deposition rate. The XPS study of the very thin films obtained by a few deposition cycles shows that the first polypyrrole layers are dedoped by hydroxydic (basic) substrate surfaces. copyright 1996 American Institute of Physics

  16. Impact of elevated precipitation, nitrogen deposition and warming on soil respiration in a temperate desert

    Science.gov (United States)

    Yue, Ping; Cui, Xiaoqing; Gong, Yanming; Li, Kaihui; Goulding, Keith; Liu, Xuejun

    2018-04-01

    Soil respiration (Rs) is the most important source of carbon dioxide emissions from soil to atmosphere. However, it is unclear what the interactive response of Rs would be to environmental changes such as elevated precipitation, nitrogen (N) deposition and warming, especially in unique temperate desert ecosystems. To investigate this an in situ field experiment was conducted in the Gurbantunggut Desert, northwest China, from September 2014 to October 2016. The results showed that precipitation and N deposition significantly increased Rs, but warming decreased Rs, except in extreme precipitation events, which was mainly through its impact on the variation of soil moisture at 5 cm depth. In addition, the interactive response of Rs to combinations of the factors was much less than that of any single-factor, and the main response was a positive effect, except for the response from the interaction of increased precipitation and high N deposition (60 kg N ha-1 yr-1). Although Rs was found to show a unimodal change pattern with the variation of soil moisture, soil temperature and soil NH4+-N content, and it was significantly positively correlated to soil dissolved organic carbon (DOC) and pH, a structural equation model found that soil temperature was the most important controlling factor. Those results indicated that Rs was mainly interactively controlled by the soil multi-environmental factors and soil nutrients, and was very sensitive to elevated precipitation, N deposition and warming. However, the interactions of multiple factors largely reduced between-year variation of Rs more than any single-factor, suggesting that the carbon cycle in temperate deserts could be profoundly influenced by positive carbon-climate feedback.

  17. Safe cycling!

    CERN Document Server

    Anaïs Schaeffer

    2012-01-01

    The HSE Unit will be running a cycling safety campaign at the entrances to CERN's restaurants on 14, 15 and 16 May. Pop along to see if they can persuade you to get back in the saddle!   With summer on its way, you might feel like getting your bike out of winter storage. Well, the HSE Unit has come up with some original ideas to remind you of some of the most basic safety rules. This year, the prevention campaign will be focussing on three themes: "Cyclists and their equipment", "The bicycle on the road", and "Other road users". This is an opportunity to think about the condition of your bike as well as how you ride it. From 14 to 16 May, representatives of the Swiss Office of Accident Prevention and the Touring Club Suisse will join members of the HSE Unit at the entrances to CERN's restaurants to give you advice on safe cycling (see box). They will also be organising three activity stands where you can test your knowle...

  18. Nitrogen deposition and prey nitrogen uptake control the nutrition of the carnivorous plant Drosera rotundifolia

    International Nuclear Information System (INIS)

    Millett, J.; Foot, G.W.; Svensson, B.M.

    2015-01-01

    Nitrogen (N) deposition has important negative impacts on natural and semi-natural ecosystems, impacting on biotic interactions across trophic levels. Low-nutrient systems are particularly sensitive to changes in N inputs and are therefore more vulnerable to N deposition. Carnivorous plants are often part of these ecosystems partly because of the additional nutrients obtained from prey. We studied the impact of N deposition on the nutrition of the carnivorous plant Drosera rotundifolia growing on 16 ombrotrophic bogs across Europe. We measured tissue N, phosphorus (P) and potassium (K) concentrations and prey and root N uptake using a natural abundance stable isotope approach. Our aim was to test the impact of N deposition on D. rotundifolia prey and root N uptake, and nutrient stoichiometry. D. rotundifolia root N uptake was strongly affected by N deposition, possibly resulting in reduced N limitation. The contribution of prey N to the N contained in D. rotundifolia ranged from 20 to 60%. N deposition reduced the maximum amount of N derived from prey, but this varied below this maximum. D. rotundifolia tissue N concentrations were a product of both root N availability and prey N uptake. Increased prey N uptake was correlated with increased tissue P concentrations indicating uptake of P from prey. N deposition therefore reduced the strength of a carnivorous plant–prey interaction, resulting in a reduction in nutrient transfer between trophic levels. We suggest that N deposition has a negative impact on D. rotundifolia and that responses to N deposition might be strongly site specific. - Highlights: • We measured nutrition of the carnivorous plant Drosera rotundifolia across Europe. • We measured tissue nutrient concentrations and prey and root N uptake at 16 sites. • Tissue N concentrations were a product of root N availability and prey N uptake. • N deposition reduced the maximum amount of N derived from prey. • N deposition reduced the strength of a

  19. Nitrogen deposition and prey nitrogen uptake control the nutrition of the carnivorous plant Drosera rotundifolia

    Energy Technology Data Exchange (ETDEWEB)

    Millett, J., E-mail: j.millett@lboro.ac.uk [Centre for Hydrological and Ecosystem Science, Department of Geography, Loughborough University, Loughborough LE11 3TU (United Kingdom); Foot, G.W. [Centre for Hydrological and Ecosystem Science, Department of Geography, Loughborough University, Loughborough LE11 3TU (United Kingdom); Svensson, B.M. [Department of Plant Ecology and Evolution, Uppsala University, Norbyvägen 18 D, SE-752 36 Uppsala (Sweden)

    2015-04-15

    Nitrogen (N) deposition has important negative impacts on natural and semi-natural ecosystems, impacting on biotic interactions across trophic levels. Low-nutrient systems are particularly sensitive to changes in N inputs and are therefore more vulnerable to N deposition. Carnivorous plants are often part of these ecosystems partly because of the additional nutrients obtained from prey. We studied the impact of N deposition on the nutrition of the carnivorous plant Drosera rotundifolia growing on 16 ombrotrophic bogs across Europe. We measured tissue N, phosphorus (P) and potassium (K) concentrations and prey and root N uptake using a natural abundance stable isotope approach. Our aim was to test the impact of N deposition on D. rotundifolia prey and root N uptake, and nutrient stoichiometry. D. rotundifolia root N uptake was strongly affected by N deposition, possibly resulting in reduced N limitation. The contribution of prey N to the N contained in D. rotundifolia ranged from 20 to 60%. N deposition reduced the maximum amount of N derived from prey, but this varied below this maximum. D. rotundifolia tissue N concentrations were a product of both root N availability and prey N uptake. Increased prey N uptake was correlated with increased tissue P concentrations indicating uptake of P from prey. N deposition therefore reduced the strength of a carnivorous plant–prey interaction, resulting in a reduction in nutrient transfer between trophic levels. We suggest that N deposition has a negative impact on D. rotundifolia and that responses to N deposition might be strongly site specific. - Highlights: • We measured nutrition of the carnivorous plant Drosera rotundifolia across Europe. • We measured tissue nutrient concentrations and prey and root N uptake at 16 sites. • Tissue N concentrations were a product of root N availability and prey N uptake. • N deposition reduced the maximum amount of N derived from prey. • N deposition reduced the strength of a

  20. Atmospheric Deposition Modeling Results

    Data.gov (United States)

    U.S. Environmental Protection Agency — This asset provides data on model results for dry and total deposition of sulfur, nitrogen and base cation species. Components include deposition velocities, dry...

  1. Electro-Deposition Laboratory

    Data.gov (United States)

    Federal Laboratory Consortium — The electro-deposition laboratory can electro-deposit various coatings onto small test samples and bench level prototypes. This facility provides the foundation for...

  2. Nutrient disequilibrium in agro-ecosystems: Concepts and case studies

    International Nuclear Information System (INIS)

    Smaling, Eric

    2002-01-01

    Full text: Amongst the problems that African agriculture faces, soil fertility decline is mentioned as a major pressure. The declining state (lower soil fertility) has led to different responses by researchers, landusers and policy makers. All responses directly or indirectly boil down to some form of 'Integrated Nutrient Management' (INM), which is defined as the 'judicious' manipulation of nutrient stocks and flows. As INM is complex and multi-faceted, it is difficult to derive simple indicators for policy makers from it. The concept of stocks (state) and flows (pressure), however, links well with economic sciences. A continental study revealed that Africa is losing nutrients at a rather alarming rate, i.e., 22 kg N, 2.5 kg P and 15 kg K per ha per year (Stoorvogel and Smaling, 1990). These values represent the sum of the outputs minus the sum of the inputs mentioned below. IN 1 mineral fertilizer OUT 1 nutrients in harvested parts, milk, meat, etc. IN 2 organic fertilizer OUT 2 nutrients in removed crop residues IN 3 atmospheric deposition OUT 3 leaching IN 4 biological N fixation OUT 4 gaseous losses IN 5 sedimentation OUT 5 runoff and erosion This study however, commissioned by FAO, had to deal with a lot of higher-scale problems, i.e., using FAO's production yearbooks, using the 1:5,000,000 FAO Soil Map of the World, generalisation, simplification, and the use of proxies (transfer functions). It triggered many studies at lower spatial scales (field, farm, village, watershed), in which inputs and outputs are accompanied by internal flows within the system. In other words, INM can be geared towards: adding nutrients to the system; saving nutrient from being lost from the system; recycling so as to maximize nutrient use efficiency. Measurement of nutrient flows is complex: a simple fertilizer trial implies adding nutrients, and harvesting part of the extra nutrients, but what happens to the nutrients that were not taken up by the crop? More spatially complex is

  3. Linking phylogenetic and functional diversity to nutrient spiraling in microbial mats from Lower Kane Cave (USA).

    Science.gov (United States)

    Engel, Annette Summers; Meisinger, Daniela B; Porter, Megan L; Payn, Robert A; Schmid, Michael; Stern, Libby A; Schleifer, K H; Lee, Natuschka M

    2010-01-01

    Microbial mats in sulfidic cave streams offer unique opportunities to study redox-based biogeochemical nutrient cycles. Previous work from Lower Kane Cave, Wyoming, USA, focused on the aerobic portion of microbial mats, dominated by putative chemolithoautotrophic, sulfur-oxidizing groups within the Epsilonproteobacteria and Gammaproteobacteria. To evaluate nutrient cycling and turnover within the whole mat system, a multidisciplinary strategy was used to characterize the anaerobic portion of the mats, including application of the full-cycle rRNA approach, the most probable number method, and geochemical and isotopic analyses. Seventeen major taxonomic bacterial groups and one archaeal group were retrieved from the anaerobic portions of the mats, dominated by Deltaproteobacteria and uncultured members of the Chloroflexi phylum. A nutrient spiraling model was applied to evaluate upstream to downstream changes in microbial diversity based on carbon and sulfur nutrient concentrations. Variability in dissolved sulfide concentrations was attributed to changes in the abundance of sulfide-oxidizing microbial groups and shifts in the occurrence and abundance of sulfate-reducing microbes. Gradients in carbon and sulfur isotopic composition indicated that released and recycled byproduct compounds from upstream microbial activities were incorporated by downstream communities. On the basis of the type of available chemical energy, the variability of nutrient species in a spiraling model may explain observed differences in microbial taxonomic affiliations and metabolic functions, thereby spatially linking microbial diversity to nutrient spiraling in the cave stream ecosystem.

  4. Methods for measuring atmospheric nitrogen deposition inputs in arid and montane ecosystems of western North America

    Science.gov (United States)

    M.E. Fenn; J.O. Sickman; A. Bytnerowicz; D.W. Clow; N.P. Molotch; J.E. Pleim; G.S. Tonnesen; K.C. Weathers; P.E. Padgett; D.H. Campbell.

    2009-01-01

    Measuring atmospheric deposition in arid and snow-dominated regions presents unique challenges. Throughfall, the flux of nutrients transported in solution to the forest floor, is generally the most practical method of estimating below-canopy deposition, particularly when monitoring multiple forest sites or over multiple years. However, more studies are needed to relate...

  5. Nutrient supply to organic agriculture as governed by EU regulations and standards in six European countries

    DEFF Research Database (Denmark)

    Løes, Anne Kristin; Bünemann, E.K.; Cooper, J.

    2017-01-01

    Organic farming systems need to replace nutrients exported via farm products, especially phosphorus (P) which may otherwise become depleted in soil in the long term. In Europe, EU regulations for organic production are shaping the farming systems with respect to inputs of nutrients. Permitted off......-farm P sources include conventional animal manure, composted or anaerobically digested organic residues, rock phosphate, and some animal residues such as meat and bone meal. The recent proposed revision of EU regulations for organic production (2014) puts less emphasis on closing nutrient cycles...

  6. Allocation of Nutrients to Somatic Tissues in Young Ovariectomized Grasshoppers

    Science.gov (United States)

    Judd, Evan T.; Hatle, John D.; Drewry, Michelle D.; Wessels, Frank J.; Hahn, Daniel A.

    2010-01-01

    The disposable soma hypothesis predicts that when reproduction is reduced, life span is increased because more nutrients are invested in the soma, increasing somatic repair. Rigorously testing the hypothesis requires tracking nutrients from ingestion to allocation to the soma or to reproduction. Fruit flies on life-extending dietary restriction increase allocation to the soma “relative” to reproduction, suggesting that allocation of nutrients can be associated with extension of life span. Here, we use stable isotopes to track ingested nutrients in ovariectomized grasshoppers during the first oviposition cycle. Previous work has shown that ovariectomy extends life span, but investment of protein in reproduction is not reduced until after the first clutch of eggs is laid. Because ovariectomy does not affect investment in reproduction at this age, the disposable soma hypothesis would predict that ovariectomy should also not affect investment in somatic tissues. We developed grasshopper diets with distinct signatures of 13C and 15N, but that produced equivalent reproductive outputs. These diets are, therefore, appropriate for the reciprocal switches in diet needed for tracking ingested nutrients. Incorporation of stable isotopes into eggs showed that grasshoppers are income breeders, especially for carbon. Allocation to the fat body of nitrogen ingested as adults was slightly increased by ovariectomy; this was our only result that was not consistent with the disposable soma hypothesis. In contrast, ovariectomy did not affect allocation of nitrogen to femoral muscles. Further, allocation of carbon to the fat body or femoral muscles did not appear to be affected by ovariectomy. Total anti-oxidant activities in the hemolymph and femoral muscles were not affected by ovariectomy. These experiments showed that allocation of nutrients was altered little by ovariectomy in young grasshoppers. Additional studies on older individuals are needed to further test the disposable

  7. Ecosystem consequences of tree monodominance for nitrogen cycling in lowland tropical forest.

    Science.gov (United States)

    Brookshire, E N Jack; Thomas, Steven A

    2013-01-01

    Understanding how plant functional traits shape nutrient limitation and cycling on land is a major challenge in ecology. This is especially true for lowland forest ecosystems of the tropics which can be taxonomically and functionally diverse and rich in bioavailable nitrogen (N). In many tropical regions, however, diverse forests occur side-by-side with monodominant forest (one species >60% of canopy); the long-term biogeochemical consequences of tree monodominance are unclear. Particularly uncertain is whether the monodominant plant-soil system modifies nutrient balance at the ecosystem level. Here, we use chemical and stable isotope techniques to examine N cycling in old-growth Mora excelsa and diverse watershed rainforests on the island of Trinidad. Across 26 small watershed forests and 4 years, we show that Mora monodominance reduces bioavailable nitrate in the plant-soil system to exceedingly low levels which, in turn, results in small hydrologic and gaseous N losses at the watershed-level relative to adjacent N-rich diverse forests. Bioavailable N in soils and streams remained low and remarkably stable through time in Mora forests; N levels in diverse forests, on the other hand, showed high sensitivity to seasonal and inter-annual rainfall variation. Total mineral N losses from diverse forests exceeded inputs from atmospheric deposition, consistent with N saturation, while losses from Mora forests did not, suggesting N limitation. Our measures suggest that this difference cannot be explained by environmental factors but instead by low internal production and efficient retention of bioavailable N in the Mora plant-soil system. These results demonstrate ecosystem-level consequences of a tree species on the N cycle opposite to cases where trees enhance ecosystem N supply via N2 fixation and suggest that, over time, Mora monodominance may generate progressive N draw-down in the plant-soil system.

  8. Ecosystem consequences of tree monodominance for nitrogen cycling in lowland tropical forest.

    Directory of Open Access Journals (Sweden)

    E N Jack Brookshire

    Full Text Available Understanding how plant functional traits shape nutrient limitation and cycling on land is a major challenge in ecology. This is especially true for lowland forest ecosystems of the tropics which can be taxonomically and functionally diverse and rich in bioavailable nitrogen (N. In many tropical regions, however, diverse forests occur side-by-side with monodominant forest (one species >60% of canopy; the long-term biogeochemical consequences of tree monodominance are unclear. Particularly uncertain is whether the monodominant plant-soil system modifies nutrient balance at the ecosystem level. Here, we use chemical and stable isotope techniques to examine N cycling in old-growth Mora excelsa and diverse watershed rainforests on the island of Trinidad. Across 26 small watershed forests and 4 years, we show that Mora monodominance reduces bioavailable nitrate in the plant-soil system to exceedingly low levels which, in turn, results in small hydrologic and gaseous N losses at the watershed-level relative to adjacent N-rich diverse forests. Bioavailable N in soils and streams remained low and remarkably stable through time in Mora forests; N levels in diverse forests, on the other hand, showed high sensitivity to seasonal and inter-annual rainfall variation. Total mineral N losses from diverse forests exceeded inputs from atmospheric deposition, consistent with N saturation, while losses from Mora forests did not, suggesting N limitation. Our measures suggest that this difference cannot be explained by environmental factors but instead by low internal production and efficient retention of bioavailable N in the Mora plant-soil system. These results demonstrate ecosystem-level consequences of a tree species on the N cycle opposite to cases where trees enhance ecosystem N supply via N2 fixation and suggest that, over time, Mora monodominance may generate progressive N draw-down in the plant-soil system.