ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    Electronic Resource
    Electronic Resource
    Experimental inducement of nitrogen saturation at the watershed scale (1993)
    s.l. : American Chemical Society
    Environmental science & technology 27 (1993), S. 565-568 
    Details
    ISSN: 1520-5851
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology , Energy, Environment Protection, Nuclear Power Engineering
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1021/es00040a017
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    reply Nitrogen deposition and carbon sequestration (1999)
    [s.l.] : Macmillan Magazines Ltd.
    Nature 400 (1999), S. 630-630 
    Details
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] Nadelhoffer et al. reply — Jenkinson et al. and Sievering are justifiably concerned that our 15N additions to forest floors do not account for the potential uptake of nitrogen input by forest canopies. We agree that canopies can remove nitrogen from the ...
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1038/23178
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Resource-based niches provide a basis for plant species diversity and dominance in arctic tundra (2002)
    [s.l.] : Macmillian Magazines Ltd.
    Nature 415 (2002), S. 68-71 
    Details
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] Ecologists have long been intrigued by the ways co-occurring species divide limiting resources. Such resource partitioning, or niche differentiation, may promote species diversity by reducing competition. Although resource partitioning is an important determinant of species diversity and ...
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1038/415068a
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    Original Articles: Dynamic Redistribution of Isotopically Labeled Cohorts of Nitrogen Inputs in Two Temperate Forests (1999)
    Springer
    Ecosystems 2 (1999), S. 4-18 
    Details
    ISSN: 1435-0629
    Keywords: Key words: tracer; simulation model; biogeochemistry; decomposition; humification; immobilization; nutrient cycling; nitrogen saturation; turnover; forest floor; synthesis.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: ABSTRACT We compared simulated time series of nitrogen-15 (15N) redistribution following a large-scale labeling experiment against field recoveries of 15NH4 + and 15NO3 − in vegetation tissues. We sought to gain insight into the altered modes of N cycling under long-term, experimentally elevated N inputs. The study took place in two contrasting forests: a red pine stand and a mixed deciduous stand (predominantly oak) at the Harvard Forest, Massachusetts, USA. We used TRACE, a dynamic simulation model of ecosystem biogeochemistry that includes 15N/14N ratios in N pools and fluxes. We simulated input–output and internal fluxes of N, tracing the labeled cohorts of N inputs through ecosystem pools for one decade. TRACE simulated the peaks and timing of 15N recovery in foliage well, providing a key link between modeling and field studies. Recovery of tracers in fine roots was captured less well. The model was structured to provide rapid, initial sinks for 15NO3 − and 15NH4 + in both forests, as indicated by field data. In simulations, N in litter turned over rapidly, even as humus provided a long-term sink for rapidly cycling N. This sink was greater in the oak forest. Plant uptake fluxes of N in these fertilized plots were on the same order of magnitude as net assimilation fluxes in forest-floor humus. A striking result was the small rate of incorporation of N in humus resulting from the transfer of litter material to humus, compared with large fluxes of N into humus and its associated microorganisms through direct transfers from pools of inorganic N in soils.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s100219900054
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 5
    Electronic Resource
    Electronic Resource
    Nitrogen Controls on Fine Root Substrate Quality in Temperate Forest Ecosystems (2000)
    Springer
    Ecosystems 3 (2000), S. 57-69 
    Details
    ISSN: 1435-0629
    Keywords: Key words: fine roots; substrate quality; nitrogen; carbon fractions; temperate forest ecosystems.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: ABSTRACT Nitrogen controls on fine root substrate quality (that is, nitrogen and carbon-fraction concentrations) were assessed using nitrogen availability gradients in the Harvard Forest chronic nitrogen addition plots, University of Wisconsin Arboretum, Blackhawk Island, Wisconsin, and New England spruce-fir transect. The 27 study sites encompassed within these four areas collectively represented a wide range of nitrogen availability (both quantity and form), soil types, species composition, aboveground net primary production, and climatic regimes. Changes in fine root substrate quality among sites were most frequently and strongly correlated with nitrate availability. For the combined data set, fine root nitrogen concentration increased (adjusted R 2 = 0.46, P 〈 0.0001) with increasing site nitrate availability. Fine root “extractive” carbon-fraction concentrations decreased (adjusted R 2 = 0.32, P 〈 0.0002), “acid-soluble” compounds increased (adjusted R 2 = 0.35, P 〈 0.0001), and the “acid-insoluble” carbon fraction remained relatively high and stable (combined mean of 48.7 ± 3.1% for all sites) with increasing nitrate availability. Consequently, the ratio of acid-insoluble C–total N decreased (adjusted R 2 = 0.40, P 〈 0.0001) along gradients of increasing nitrate availability. The coefficients of determination for significant linear regressions between site nitrate availability and fine root nitrogen and carbon-fraction concentrations were generally higher for sites within each of the four study areas. Within individual study sites, tissue substrate quality varied between roots in different soil horizons and between roots of different size classes. However, the temporal variation of fine root substrate quality indices within specific horizons was relatively low. The results of this study indicate that fine root substrate quality increases with increasing nitrogen availability and thus supports the substrate quality component of a hypothesized conceptual model of nitrogen controls on fine root dynamics that maintains that fine root production, mortality, substrate quality, and decomposition increase with nitrogen availability in forest ecosystems in a manner that is analogous to foliage.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s100210000010
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 6
    Electronic Resource
    Electronic Resource
    Long-Term Nitrogen Additions and Nitrogen Saturation in Two Temperate Forests (2000)
    Springer
    Ecosystems 3 (2000), S. 238-253 
    Details
    ISSN: 1435-0629
    Keywords: Key words: ammonium nitrate; biomass production; foliar chemistry; net mineralization; net nitrification; nitrogen deposition; nitrogen saturation; soil solution chemistry.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: ABSTRACT This article reports responses of two different forest ecosystems to 9 years (1988–96) of chronic nitrogen (N) additions at the Harvard Forest, Petersham, Massachusetts. Ammonium nitrate (NH4NO3) was applied to a pine plantation and a native deciduous broad-leaved (hardwood) forest in six equal monthly doses (May–September) at four rates: control (no fertilizer addition), low N (5 g N m-2 y-1), high N (15 g N m-2 y-1), and low N + sulfur (5 g N m-2 y-1 plus 7.4 g S m-2 y-1). Measurements were made of net N mineralization, net nitrification, N retention, wood production, foliar N content and litter production, soil C and N content, and concentrations of dissolved organic carbon (DOC) and nitrogen (DON) in soil water. In the pine stand, nitrate losses were measured after the first year of additions (1989) in the high N plot and increased again in 1995 and 1996. The hardwood stand showed no significant increases in nitrate leaching until 1995 (high N only), with further increases in 1996. Overall N retention efficiency (percentage of added N retained) over the 9-year period was 97–100% in the control and low N plots of both stands, 96% in the hardwood high N plot, and 85% in the pine high N plot. Storage in aboveground biomass, fine roots, and soil extractable pools accounted for only 16–32% of the added N retained in the amended plots, suggesting that the one major unmeasured pool, soil organic matter, contains the remaining 68–84%. Short-term redistribution of 15N tracer at natural abundance levels showed similar division between plant and soil pools. Direct measurements of changes in total soil C and N pools were inconclusive due to high variation in both stands. Woody biomass production increased in the hardwood high N plot but was significantly reduced in the pine high N plot, relative to controls. A drought-induced increase in foliar litterfall in the pine stand in 1995 is one possible factor leading to a measured increase in N mineralization, nitrification, and nitrate loss in the pine high N plot in 1996.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s100210000023
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 7
    Electronic Resource
    Electronic Resource
    Nitrogen deposition makes a minor contribution to carbon sequestration in temperate forests (1999)
    [s.l.] : Macmillan Magazines Ltd.
    Nature 398 (1999), S. 145-148 
    Details
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] Humans have altered global nitrogen cycling such that more atmospheric N2 is being converted (‘fixed’) into biologically reactive forms by anthropogenic activities than by all natural processes combined. In particular, nitrogen oxides emitted during fuel combustion and ...
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1038/18205
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 8
    Electronic Resource
    Electronic Resource
    Roots exert a strong influence on the temperature sensitivityof soil respiration (1998)
    [s.l.] : Macmillan Magazines Ltd.
    Nature 396 (1998), S. 570-572 
    Details
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] The temperature sensitivity of soil respiration will largely determine the effects of a warmer world on net carbon flux from soils to the atmosphere. CO2 flux from soils to the atmosphere is estimated to be 50–70 petagrams of carbon per year and makes up 20–38% of annual ...
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1038/25119
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 9
    Electronic Resource
    Electronic Resource
    Immobilization of a 15N-labeled nitrate addition by decomposing forest litter (1996)
    Springer
    Oecologia 105 (1996), S. 141-150 
    Details
    ISSN: 1432-1939
    Keywords: Decomposition ; N immobilization ; N saturation ; Nitrate ; 15N
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Effects of chronic HNO3 and H2SO4 additions on decomposition of senesced birch leaf, beech leaf, spruce needle, and wood chip litters were examined. Litters were incubated for up to 4 years in fiberglass mesh (1 mm) bags on experimental plots in a mixed-species forest near the Bear Brooks Watershed Manipulation (BBWM) site in eastern Maine, United States. Plot treatments included HNO3 additions at 28 and 56 kg N·ha−1·year−1, H2SO4 additions at 128 kg S·ha−1·year−1, and a combined HNO3 and H2SO4 treatment at 28 kg N and 64 kg S ·ha−1·year−1. The 15N content of all NO3 added was artificially increased to 344% δ15N. Litter bags were collected each fall and analyzed for organic matter loss, nitrogen concentration, and 15N abundance throughout the 4-year experiment. Extractive (non-polar-soluble+water-soluble), cellulose (acid-soluble), and lignin (acid-insoluble) fractions were analyzed for the first 2 years. In wood chips, nitrogen additions increased mass loss and N concentration, but not the mass of N after 4 years. Neither N nor S additions had large effects on mass loss, N concentration, or N content of leaf litters. All litters immobilized and mineralized N simultaneously, but we were able to place a lower bound on gross N immobilization by mass balancing 15N additions. Birch and spruce litters showed net mineralization, while beech leaf and wood chip litters showed net immobilization. Net immobilizing litters were those with the highest initial cellulose concentration (wood chips=80% beech leaves=54%), and we attribute the higher capacity for immobilization to more readily available carbon. Lignin mass increased initially in all litter types except spruce needles. Also, extractives in net immobilizing litters either increased initially (wood chips) or decreased at a slower rate than bulk litter (beech leaves). We calculate the potential of decomposing litter to immobilize exogenous nitrate in this system to be 1–1.5 kg N·ha−1·year−1, which is about half of the usual NO3 deposition at this site, but only a small fraction of the experimental addition.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00328539
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 10
    Electronic Resource
    Electronic Resource
    A 15N tracer technique for assessing fine root production and mortality (1997)
    Springer
    Oecologia 112 (1997), S. 300-304 
    Details
    ISSN: 1432-1939
    Keywords: Key words Fine roots ; Production ; Mortality ; 15N ; Methodology
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract We tested a 15N tracer technique to assess fine root production and mortality based on temporal measurements of the 15N mass in fine root structural tissues and the 15N concentration of the plant-available soil N pool. The results of a pilot study indicated that this technique is based on sound methods and reasonable assumptions. The 15N tracer technique avoids most of the major limitations which hinder existing methods and may provide valuable insight into the rates and controls of fine root production and mortality in terrestrial ecosystems.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004420050312
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...