 |
| Titel |
Overlooked runaway feedback in the marine nitrogen cycle: the vicious cycle |
| VerfasserIn |
A. Landolfi, H. Dietze, W. Koeve, A. Oschlies |
| Medientyp |
Artikel
|
| Sprache |
Englisch
|
| ISSN |
1726-4170
|
| Digitales Dokument |
URL |
| Erschienen |
In: Biogeosciences ; 10, no. 3 ; Nr. 10, no. 3 (2013-03-01), S.1351-1363 |
| Datensatznummer |
250018128
|
| Publikation (Nr.) |
 copernicus.org/bg-10-1351-2013.pdf |
|
|
|
|
|
| Zusammenfassung |
| The marine nitrogen (N) inventory is thought to be stabilized by negative
feedback mechanisms that reduce N inventory excursions relative to the more
slowly overturning phosphorus inventory. Using a global biogeochemical ocean
circulation model we show that negative feedbacks stabilizing the N inventory
cannot persist if a close spatial association of N2 fixation and
denitrification occurs. In our idealized model experiments, nitrogen deficient
waters, generated by denitrification, stimulate local N2 fixation
activity. But, because of stoichiometric constraints, the denitrification of
newly fixed nitrogen leads to a net loss of N. This can enhance the N
deficit, thereby triggering additional fixation in a vicious cycle,
ultimately leading to a runaway N loss. To break this vicious cycle, and
allow for stabilizing negative feedbacks to occur, inputs of new N need to be
spatially decoupled from denitrification. Our idealized model experiments
suggest that factors such as iron limitation or dissolved organic matter
cycling can promote such decoupling and allow for negative feedbacks that
stabilize the N inventory. Conversely, close spatial co-location of
N2 fixation and denitrification could lead to net N loss. |
| |
|
| Teil von |
|
|
|
|
|
|
|
|