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| Titel |
Characteristic of riverine dissolved inorganic nitrogen export in subtropic high-standing island, Taiwan |
| VerfasserIn |
Li-Chin Lee, Jr-Chuan Huang, Tsung-Yu Lee, Yu-ting Shih |
| Konferenz |
EGU General Assembly 2015
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 17 (2015) |
| Datensatznummer |
250108314
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| Publikation (Nr.) |
 EGU/EGU2015-8065.pdf |
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| Zusammenfassung |
| Extreme increase of anthropogenic nitrogen (e.g. fertilizer and excretion) has altered the
nitrogen cycling and terrestrial ecosystems. Taiwan located between eastern Asia
and Oceania is the hotspot of global riverine DIN (dissolved inorganic nitrogen,
including NH4, NO3, and NO2) export, but rarely documented comprehensively.
Totally 50 catchments, covering 2/3 of this island, with different anthropogenic
activities are involved in this study. The monthly sampling for NH4 and seasonal
sampling for NO3 and NO2 supplemented with daily discharge are used to estimate
the riverine DIN export. Meanwhile, the landscape characteristics, land-use, and
population density are also used to discriminate the characteristics of riverine DIN
export.
Results showed that the observed riverine DIN concentration and yield vary from
17.7-603.5 μM and 575.0-15588.9 kg-N km-2 yr-1 corresponding to the increase of
anthropogenic activities. The arithmetic mean of DIN concentration and yield are 126.7μM
and 3594.7 kg-N km-2 yr-1, respectively. The unexpected high yields can attribute to
abundant precipitation, heavy fertilizer application, and high population. For concentration
variation, no significant variation can be found in the pristine and agriculture-dominated
catchments, whereas the strong dilution effect in the wet season is characterized in the
intensively-disturbed catchments. Although there are some seasonal variations in
concentration, the yields in wet season are almost doubled than that in dry season
indicating the strong control of streamflow. For speciation, NH4 is the dominant
species in intensively-disturbed catchment, but NO3 dominates the DIN composition
for the pristine and agriculture-dominated catchments. Our result can provide a
strong basis for supplementary estimation for regional to global study and DIN
export control which is the aim of the Kampala Declaration on global nitrogen
management.
Keywords: dissolved inorganic nitrogen, anthropogenic nitrogen, Taiwan. |
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