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| Titel |
Element export from a small catchment in the tropical montane forest of Ecuador responds to climate change |
| VerfasserIn |
Sophia Leimer, Elias Willimann, Abdallah Alaoui, Katja Trachte, Wolfgang Wilcke |
| 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 |
250103136
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| Publikation (Nr.) |
 EGU/EGU2015-5297.pdf |
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| Zusammenfassung |
| In a very remote tropical montane rain forest in the Ecuadorian Andes on the rim of the
Amazon basin, increasing temperatures, longer dry spells, and an associated reduction in soil
moisture were observed in the past 15 years. In the study ecosystem, element exports from a
9-ha large catchment with stream water are linked to the depth of water flow through soil
because of vertical variations in soil chemical properties. The further increase in temperature
and precipitation, as predicted by climate models, will have an impact on the water flow paths
in soil and therefore alter element exports. Hence, we investigated how future element exports
from this catchment in Ecuador will develop under the emission scenarios A1B
and B1 for the decades 2050-2059 and 2090-2099 compared to current element
exports.
Discharge from the study catchment was measured in 1998-2013, partly in high resolution.
Element concentrations in stream water (total organic carbon, NO3-N, NH4-N, dissolved
organic nitrogen, PO4-P, total dissolved phosphorus, S, Cl, K, Ca, Mg, Na, Zn, Al, Mn) were
measured in 1998-2012 in weekly resolution. Based on catchment properties, measured
climate, and water flow data, discharge in 1998-2013 was simulated in daily resolution with
the hydrological model WaSiM. From the hydrograph of surface flow, three flow classes
(baseflow, intermediate, storm) were separated and linked with stream chemical properties.
Element concentrations in stream water were grouped according to the flow classes and mean
concentrations per flow class were calculated. Subsequently, the mean element
concentration was multiplied with the mean of the annual discharge sums per flow class
resulting in current element exports. For estimations of future element exports with
stream water, discharge was simulated under the emission scenarios A1B and B1 for
the decades 2050-2059 and 2090-2099 and separated into the three flow classes.
Future element exports per scenario were calculated according to the current element
exports.
In both climate scenarios and decades, the number of days with high discharge rates (storm)
increased and with low discharge rates (baseflow) decreased. Mean discharge rates increased
by 7.5-21 % until the end of the 21st century. Annual exports of most elements were
predicted to increase, particularly exports of the metals Al, Zn, and Mn (up to + 53% by the
end of the 21st century) but also of NO3-N (+ 27%) while P exports remain unchanged. Our
results demonstrate that climate change might considerably affect future element exports
from this tropical montane catchment because of changing water flow paths through
soil. |
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