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| Titel |
Decreased carbon limitation of litter respiration in a mortality-affected piñon–juniper woodland |
| VerfasserIn |
E. Berryman, J. D. Marshall, T. Rahn, M. Litvak, J. Butnor |
| 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 ; 10, no. 3 ; Nr. 10, no. 3 (2013-03-11), S.1625-1634 |
| Datensatznummer |
250018144
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| Publikation (Nr.) |
 copernicus.org/bg-10-1625-2013.pdf |
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| Zusammenfassung |
| Microbial respiration depends on microclimatic variables and carbon (C)
substrate availability, all of which are altered when ecosystems experience
major disturbance. Widespread tree mortality, currently affecting
piñon–juniper ecosystems in southwestern North America, may affect C
substrate availability in several ways, for example, via litterfall pulses
and loss of root exudation. To determine piñon mortality effects on C and
water limitation of microbial respiration, we applied field amendments
(sucrose and water) to two piñon–juniper sites in central New Mexico,
USA: one with a recent (< 1 yr), experimentally induced mortality
event and a nearby site with live canopy. We monitored the respiration
response to water and sucrose applications to the litter surface and to the
underlying mineral soil surface, testing the following hypotheses: (1) soil
respiration in a piñon–juniper woodland is water- and labile C-limited in
both the litter layer and mineral soil; (2) piñon mortality reduces the C
limitation of litter respiration; and (3) piñon mortality enhances the C
limitation of mineral soil respiration. Litter respiration at both sites
responded to increased water availability, yet surprisingly, mineral soil
respiration was not limited by water. Consistent with hypothesis 2, C
limitation of litter respiration was lower at the recent mortality site
compared to the intact canopy site. Applications to the mineral soil showed
evidence of reduction in CO2 flux on the girdled site and a
non-significant increase on the control. We speculate that the reduction may
have been driven by water-induced carbonate dissolution, which serves as a sink
for CO2 and would reduce the net flux. Widespread piñon mortality
may decrease labile C limitation of litter respiration, at least during the
first growing season following mortality. |
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