Nitrogen uptake by <i>Hylocomium splendens</i> during snowmelt in a boreal forest
Bibliographic record
Abstract
AbstractIn most boreal regions snow composes a large portion of the annual precipitation. Although many boreal forest floor bryophytes depend largely on precipitation for their nitrogen (N) supply, bryophyte uptake of snow N is little explored. We studied chemical forms of plant-accessible N in snowmelt, as well as the temporal dynamics of their release. In conjunction we performed a N uptake experiment using the common boreal bryophyte Hylocomium splendens. The results demonstrated that the snowmelt N pool was dominated by NO3− (86%), followed by NH4+ (11%) and amino acid N (3%), in total providing ca 0.3 kg N·ha−1 to the forest floor vegetation. Hylocomium splendens was able to access both inorganic and organic 15N labelled N forms (NO3−, NH4+, and glycine) applied in situ to the snow covering the moss prior to snowmelt. Across all the N forms H. splendens took up ca 24% of the snow-deposited N. Nitrate uptake exceeded that of glycine, while NH4+ uptake was intermediate, reflecting the ambient distribution of the snowmelt N pool between plant-accessible N forms.RésuméDans la plupart des régions boréales, une proportion importante des précipitations annuelles tombe sous forme de neige. Bien que plusieurs bryophytes du sol de la forêt boréale dépendent en grande partie des précipitations pour leur approvisionnement en azote (N), l'assimilation du N de la neige par les bryophytes est peu explorée. Nous avons étudié les formes chimiques de N accessibles aux plantes dans l'eau de fonte de la neige, ainsi que la dynamique temporelle de leur disponibilité. Nous avons aussi effectué une expérience d'assimilation de N utilisant Hylocomium splendens, une espèce boréale commune de bryophytes. Les résultats ont démontré que NO3− dominait le pool de N dans l'eau de fonte de la neige (86%), suivi par NH4+ (11%) et par l'acide aminé N (3%) fournissant au total ca 0.3 kg N·ha−1 à la végétation du sol forestier. H. splendens était capable d'accéder aux formes de N identifiées au 15N tant inorganiques qu'organiques (NO3−, NH4+ et glycine) ajoutées in situ à la neige couvrant la mousse avant la fonte. De toutes les formes de N, H. splendens a utilisé ca 24% du N déposé par la neige. L'assimilation du nitrate a excédé celui de la glycine, tandis que l'assimilation de NH4+ était intermédiaire, reflétant la distribution ambiante de N dans l'eau de fonte de la neige entre les formes de N accessibles aux plantes.Keywords: amino acid Nammoniumbryophyte ecophysiologynitrateMots-clés: acide aminé Nammoniumécophysiologie des bryophytesnitrate
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one teacher head, not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".