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  • dissolved organic nitrogen  (2)
  • flooded forest  (2)
  • Springer  (4)
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  • Springer  (4)
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  • 1
    Electronic Resource
    Electronic Resource
    Nitrogen yields from undisturbed watersheds in the Americas (1999)
    Springer
    Biogeochemistry 46 (1999), S. 149-162 
    Details
    ISSN: 1573-515X
    Keywords: dissolved organic nitrogen ; nitrogen concentrations ; nitrogen cycle ; nitrogen yields ; nitrate
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Geosciences
    Notes: Abstract Yields of total fixed nitrogen and nitrogen fractions are summarized for thirty-one watersheds in which anthropogenic disturbance of the nitrogen cycle, either through land use or atmospheric deposition, is negligible or slight. These yields are taken as representative of background conditions over a broad range of watershed areas, elevations, and vegetation types. The data set focuses on watersheds of the American tropics, but also includes information on the Gambia River (Africa) and some small watersheds in the Sierra Nevada of California. For the tropical watersheds, total nitrogen yield averages 5.1 kg ha−1 y−1. On average, 30% of the total is particulate and 70% is dissolved. Of the dissolved fraction, an average of 50% is organic and 50% is inorganic, of which 20% is ammonium and 80% is nitrate. Yields are substantially lower than previously estimated for background conditions. Yields of all nitrogen fractions are strongly related to runoff, which also explains a large percentage of variance in yield of total nitrogen (r2=0.85). For total nitrogen and nitrogen fractions, yield increases at about two-thirds the rate of runoff; concentration decreases as runoff increases. There is a secondary but significant positive relationship between elevation and yield of DIN. Ratios DON/TDN and PN/TN both are related to watershed area rather than runoff; DON/TDN decreases and PN/TN increases toward higher stream orders. The analysis suggests for tropical watersheds the existence of mechanisms promoting strong homeostasis in the yield of N and its fractions for a given moisture regime, as well as predictable downstream change in proportionate representation N fractions. Yields and concentrations for small tropical watersheds are much larger than for the few temperate ones with which comparisons are possible.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01007577
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  • 2
    Electronic Resource
    Electronic Resource
    Nitrogen yields from undisturbed watersheds in the Americas (1999)
    Springer
    Biogeochemistry 46 (1999), S. 149-162 
    Details
    ISSN: 1573-515X
    Keywords: dissolved organic nitrogen ; nitrogen concentrations ; nitrogen cycle ; nitrogen yields ; nitrate
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Geosciences
    Notes: Abstract Yields of total fixed nitrogen and nitrogen fractions are summarized for thirty-one watersheds in which anthropogenic disturbance of the nitrogen cycle, either through land use or atmospheric deposition, is negligible or slight. These yields are taken as representative of background conditions over a broad range of watershed areas, elevations, and vegetation types. The data set focuses on watersheds of the American tropics, but also includes information on the Gambia River (Africa) and some small watersheds in the Sierra Nevada of California. For the tropical watersheds, total nitrogen yield averages 5.1 kg ha −1 y−1. On average, 30% of the total is particulate and 70% is dissolved. Of the dissolved fraction, an average of 50% is organic and 50% is inorganic, of which 20% is ammonium and 80% is nitrate. Yields are substantially lower than previously estimated for background conditions. Yields of all nitrogen fractions are strongly related to runoff, which also explains a large percentage of variance in yield of total nitrogen (r2 = 0.85). For total nitrogen and nitrogen fractions, yield increases at about two-thirds the rate of runoff; concentration decreases as runoff increases. There is a secondary but significant positive relationship between elevation and yield of DIN. Ratios DON/TDN and PN/TN both are related to watershed area rather than runoff; DON/TDN decreases and PN/TN increases toward higher stream orders. The analysis suggests for tropical watersheds the existence of mechanisms promoting strong homeostasis in the yield of N and its fractions for a given moisture regime, as well as predictable downstream change in proportionate representation N fractions. Yields and concentrations for small tropical watersheds are much larger than for the few temperate ones with which comparisons are possible.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1006108315578
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  • 3
    Electronic Resource
    Electronic Resource
    Composition and deposition of throughfall in a flooded forest archipelago (1999)
    Springer
    Biogeochemistry 45 (1999), S. 169-195 
    Details
    ISSN: 1573-515X
    Keywords: Amazon ; flooded forest ; Negro River ; rain ; solutes ; throughfall
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Geosciences
    Notes: Abstract The sources of spatial and temporal variation and rates of nutrient deposition via throughfall were studied for 9 months in the Anavilhanas archipelago of the Negro River, Brazil. A total of 30 events was sampled individually for rain and throughfall chemistry in a 1-ha plot of flooded forest. Throughfall samples were collected in 40 collectors distributed in five parallel transects in the study plot, while rain was collected in 4 collectors in an adjacent channel. Volume-weighted mean (VWM) concentrations of solutes in rain were consistently lower than in throughfall, except for H+, NO3- and NH4+. Ratios of VWM concentrations of rain to throughfall indicated that K+, followed by Mg2+ and PO43-, were the most enhanced solutes as rain passed through the forest canopy. The deposition of solutes varied significantly among transects, except for Na+ and Ca2+, and was significantly correlated with maximum flooding depth, foliar nutrient content soil fertility and canopy closure for most solutes. The concentrations of PO43- and most major ions were higher in throughfall compared to those in rain due to canopy exchange and dry deposition. In contrast, NO3-, NH4+ and H+ were retained due to immobilization by leafy canopy and ion exchange processes. Solute inputs via throughfall (not including stemflow) to a floodplain lake (Lake Prato) of the archipelago accounted for 30 to 64% of the total for most solutes in the lake at high water, which indicates that throughfall is an important source of nutrients to the aquatic ecosystem of the Anavilhanas archipelago.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1006108618196
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  • 4
    Electronic Resource
    Electronic Resource
    Composition and deposition of throughfall in a flooded forest archipelago (Negro River, Brazil) (1999)
    Springer
    Biogeochemistry 45 (1999), S. 169-195 
    Details
    ISSN: 1573-515X
    Keywords: Amazon ; flooded forest ; Negro River ; rain ; solutes ; throughfall
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Geosciences
    Notes: Abstract The sources of spatial and temporal variation and rates of nutrient deposition via throughfall were studied for 9 months in the Anavilhanas archipelago of the Negro River, Brazil. A total of 30 events was sampled individually for rain and throughfall chemistry in a 1-ha plot of flooded forest. Throughfall samples were collected in 40 collectors distributed in five parallel transects in the study plot, while rain was collected in 4 collectors in an adjacent channel. Volume-weighted mean (VWM) concentrations of solutes in rain were consistently lower than in throughfall, except for H+, NO 3 − and NH 4 + . Ratios of VWM concentrations of rain to throughfall indicated that K+, followed by Mg2+ and PO 4 3− , were the most enhanced solutes as rain passed through the forest canopy. The deposition of solutes varied significantly among transects, except for Na+ and Ca2+, and was significantly correlated with maximum flooding depth, foliar nutrient content, soil fertility and canopy closure for most solutes. The concentrations of PO 4 3− and most major ions were higher in throughfall compared to those in rain due to canopy exchange and dry deposition. In contrast, NO 3 − , NH 4 + and H+ were retained due to immobilization by leafy canopy and ion exchange processes. Solute inputs via throughfall (not including stemflow) to a floodplain lake (Lake Prato) of the archipelago accounted for 30 to 64% of the total for most solutes in the lake at high water, which indicates that throughfall is an important source of nutrients to the aquatic ecosystem of the Anavilhanas archipelago.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01106780
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    Paper (German National Licenses)
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