Feather moss nitrogen acquisition across natural fertility gradients in boreal forests

Rousk, Kathrin; Rousk, Johannes; Jones, Davey L.; Zackrisson, Olle, et al. (2013). Feather moss nitrogen acquisition across natural fertility gradients in boreal forests. Soil Biology & Biochemistry, 61,, 86 - 95
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DOI:
| Published | English
Authors:
Rousk, Kathrin ; Rousk, Johannes ; Jones, Davey L. ; Zackrisson, Olle , et al.
Department:
MEMEG
BECC: Biodiversity and Ecosystem services in a Changing Climate
Microbial Ecology
Research Group:
Microbial Ecology
Abstract:
Feather mosses utilize various sources of nitrogen (N): they absorb N deposited on leaf tissue, they host N-2 fixing cyanobacteria, and they are able to take up N directly from soil. In addition to their importance as primary producers in boreal ecosystems, feather mosses play a significant role in N cycling. However, estimates of their ability to take up N from soil in situ are scarce. Further, connecting uptake of N from soil with N-2 fixation could significantly improve our understanding of their role in ecosystem N cycling, but to date this issue has not been addressed. We report results from an uptake experiment in which we tracked C-13-carbon (C), N-15-alanine and N-15-ammonium chloride (NH4Cl) into feather moss (Pleurozium schreberi (Brid.) Mitt.)-soil cores taken along natural fertility gradients in Northern Sweden. The varying fertility conditions coincided with a N-2 fixation gradient in the feather moss. We found that P. schreberi takes up C and N directly from soil. However, the moss did not show a preference for inorganic or organic N sources and only 1.4% of the added amino acid appeared to be taken up from soil in an intact form. No differences in uptake of C or N from soil along the fertility gradients were detected. Nitrogen fixation rates in the moss were thus not correlated with C or N-uptake from soil. Nitrogen fixation as well as uptake of C and N from soil seem to be unaffected by C or N availability in the soil, suggesting that the moss can cover its nutrient demand by absorption of throughfall N and via associated N-2-fixing cyanobacteria without soil-N supplementation. We suggest further, that the moss can represent a (temporary) N-sink in the boreal forest, and that the moss' mechanism of uptake and release thereby will characterize the ecosystem N cycle. (C) 2013 Elsevier Ltd. All rights reserved.
Keywords:
Acetylene reduction ; Bryophytes ; Cyanobacteria ; Microbial community ; N ; deposition ; N limitation ; Organic nitrogen
ISSN:
0038-0717
LUP-ID:
bafb855f-88e5-4a04-ad54-595955b99fbb | Link: https://lup.lub.lu.se/record/bafb855f-88e5-4a04-ad54-595955b99fbb | Statistics

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