Exposure to nitrogen does not eliminate N₂ fixation in the feather moss Pleurozium schreberi (Brid.) Mitt.

TY - JOUR

T1 - Exposure to nitrogen does not eliminate N2 fixation in the feather moss Pleurozium schreberi (Brid.) Mitt.

AU - Rousk, Kathrin

AU - Jones, Davey L.

AU - DeLuca, Thomas H.

PY - 2014/1

Y1 - 2014/1

N2 - Background and aims: The feather moss Pleurozium schreberi (Brid.) Mitt. is colonized by cyanobacteria, which fix substantial amounts of atmospheric nitrogen (N) in pristine and N-poor ecosystems. Cyanobacterial N2 fixation is inhibited by N deposition. However, the threshold of N input that leads to the inhibition of N2 fixation has not been adequately investigated. Further, the ability of N2 fixation to recover in mosses from high N deposition areas has not been studied to date. Methods: We conducted two laboratory studies in which we (1) applied a range of concentrations of N as NH4NO3 to mosses from low N-deposition areas, and (2) we deprived mosses from a high N-deposition area of N to test their ability to recover N2 fixation. Results: Higher addition rates (up to 10 kg N ha-1) did not systematically inhibit N2 fixation in P. schreberi. Conversely, upon weeks of N deprivation of mosses from a high N environment, N2 fixation rates increased. Conclusions: The threshold of total N deposition above which N2 fixation in P. schreberi is inhibited is likely to be > 10 kg N ha-1. Further, cyanobacteria are able to recover from high N inputs and are able to fix atmospheric N2 after a period of N deprivation.

AB - Background and aims: The feather moss Pleurozium schreberi (Brid.) Mitt. is colonized by cyanobacteria, which fix substantial amounts of atmospheric nitrogen (N) in pristine and N-poor ecosystems. Cyanobacterial N2 fixation is inhibited by N deposition. However, the threshold of N input that leads to the inhibition of N2 fixation has not been adequately investigated. Further, the ability of N2 fixation to recover in mosses from high N deposition areas has not been studied to date. Methods: We conducted two laboratory studies in which we (1) applied a range of concentrations of N as NH4NO3 to mosses from low N-deposition areas, and (2) we deprived mosses from a high N-deposition area of N to test their ability to recover N2 fixation. Results: Higher addition rates (up to 10 kg N ha-1) did not systematically inhibit N2 fixation in P. schreberi. Conversely, upon weeks of N deprivation of mosses from a high N environment, N2 fixation rates increased. Conclusions: The threshold of total N deposition above which N2 fixation in P. schreberi is inhibited is likely to be > 10 kg N ha-1. Further, cyanobacteria are able to recover from high N inputs and are able to fix atmospheric N2 after a period of N deprivation.

U2 - 10.1007/s11104-013-1908-5

DO - 10.1007/s11104-013-1908-5

M3 - Journal article

AN - SCOPUS:84890861355

SN - 0032-079X

VL - 374

SP - 513

EP - 521

JO - Plant and Soil

JF - Plant and Soil

IS - 1-2

ER -