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| Titel |
Export, biodegradation, and disinfection byproduct formation of dissolved and particulate organic carbon in a forested headwater stream during extreme rainfall events |
| VerfasserIn |
B.-J. Jung, J.-K. Lee, H. Kim, J.-H. Park |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1726-4170
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| Digitales Dokument |
URL |
| Erschienen |
In: Biogeosciences ; 11, no. 21 ; Nr. 11, no. 21 (2014-11-13), S.6119-6129 |
| Datensatznummer |
250117670
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| Publikation (Nr.) |
 copernicus.org/bg-11-6119-2014.pdf |
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| Zusammenfassung |
| Despite an increasing recognition of the importance of extreme rainfall
events for organic carbon export to inland waters, little attention has been
paid to the export and reactivity of particulate organic carbon (POC) and
dissolved organic C (DOC) in mountainous headwater watersheds under monsoon
climates. To investigate environmental implications of storm-enhanced export
of POC and DOC in mountainous headwater streams, we examined the
relationships between storm magnitude and C export from a forested watershed
in the Haean Basin, South Korea, during 13 storm events over 4 years and
compared potentials of DOC and POC for biodegradation and disinfection
byproduct (DBP) formation during an extreme rainfall event with a total
rainfall of 209 mm. Event mean concentrations and export of POC increased
nonlinearly above thresholds of precipitation and discharge, far exceeding
the relatively small increases of DOC. The export of POC during a few storm
events with a total rainfall above 200 mm per event exceeded the annual
organic C export during dry years. During the 209 mm storm event,
concentrations of total trihalomethanes formed by POC-derived dissolved
components changed synchronously with POC concentrations, exhibiting lower
levels than those formed by DOC. During a 30-day incubation at 25 °C,
DOC exported during peak flow exhibited rapid biodegradation of labile
components within 7 days. In contrast, the concentrations of DOC leached
from POC gradually increased following the initial decline. Gradual
transformation of POC-derived dissolved materials resulted in greater
increases in the intensity of fulvic- and humic-like fluorescent components
compared to the DOC treatment. The results highlight the significance of
extreme rainfall events as "hot moments" for POC export from mountainous
watersheds and also suggest that storm pulses of POC can provide potential
sources of reactive organic components that can rapidly biodegrade and form
DBPs after being released into headwater streams. |
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