Benthic nitrogen regeneration, fixation, and denitrification in a temperate, eutrophic lake: Effects on the nitrogen budget and cyanobacteria blooms
Bibliographic record
Abstract
Abstract Nitrogen (N) transformations and fluxes at the sediment‐water interface (SWI) were measured in Missisquoi Bay, Lake Champlain, to clarify the role of N in cyanobacterial blooms in temperate, eutrophic lakes. N sources (e.g., N fixation and tributary inputs), sinks (e.g., denitrification/anammox), and internal “links” (e.g., dissimilatory reduction to ; DNRA) were evaluated at a river discharge (PRM) and in the central basin (MB). Sediments were a more effective sink at PRM than MB. Sediments at both sites were a net source to the water column, but DNRA was not a consistent regeneration pathway. Net N2 production at PRM in summer reversed to net N2 consumption/fixation in fall. MB sediments produced N2 at lower rates than PRM; these rates also reversed late in the season. Denitrification was limited by , especially at MB, and anammox may have contributed up to 10% of total N2 production. Sediment N2 fixation occurred simultaneously with denitrification throughout the ice‐free season and, on average, compensated 25–30% of total microbial N losses. A bottom‐water hypoxia event at MB in early July 2009 altered the N cycle, with lower actual denitrification rates and higher effluxes (not from DNRA), while phosphorus (P) flux was unaffected. The hypoxia‐altered N transformation pathways enhanced N bioavailability (but not P) and may have contributed to a non‐N‐fixing cyanobacterial bloom (Microcystis) observed 5 d later. A preliminary N budget incorporating sediment and water column sources and sinks and external loads suggested an ecosystem‐wide N deficit.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| 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 source (direct Gemma or distilled Codex), 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".