Abstract
Uncertainty about controls on long-term carbon (C) and nitrogen (N) balance, turnover, and isotopic composition currently limits our ability to predict ecosystem response to disturbance and landscape change. We used a two-century, postglacial chronosequence in Glacier Bay, Alaska, to explore the influence of C and N dynamics on soil and leaf stable isotopes. C dynamics were closely linked to soil hydrology, with increasing soil water retention during ecosystem development resulting in a linear decrease in foliar and soil δ13C, independent of shifts in vegetation cover and despite constant precipitation across sites. N dynamics responded to interactions among soil development, vegetation type, microbial activity, and topography. Contrary to the predictions of nutrient retention theory, potential nitrification and denitrification were high, relative to inorganic N stocks, from the beginning of the chronosequence, and gaseous and hydrological N losses were highest at mid-successional sites, 140–165 years since deglaciation. Though leaching of dissolved N is considered the predominant pathway of N loss at high latitudes, we found that gaseous N loss was more tightly correlated with δ15N enrichment. These results suggest that δ13C in leaves and soil can depend as much on soil development and associated water availability as on climate and that N availability and export depend on interactions between physical and biological state factors.
Original language | English |
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Number of pages | 17 |
Journal | Ecosystems |
Early online date | 13 Apr 2018 |
DOIs | |
Publication status | E-pub ahead of print - 13 Apr 2018 |
Keywords
- C
- N
- denitrification
- foliar
- Glacier Bay
- nitrification
- nutrient retention theory
- primary succession
- soil
- water use efficiency
ASJC Scopus subject areas
- Ecology, Evolution, Behavior and Systematics
- Environmental Chemistry
- Ecology