Advection of freshwater phytoplankton in the St. Lawrence River estuarine turbidity maximum as revealed by sulfur-stable isotopes
Bibliographic record
Abstract
MEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections MEPS 372:19-29 (2008) - DOI: https://doi.org/10.3354/meps07685 Advection of freshwater phytoplankton in the St. Lawrence River estuarine turbidity maximum as revealed by sulfur-stable isotopes Jean-François Lapierre, Jean-Jacques Frenette* Université du Québec à Trois-Rivières, Département de Chimie-Biologie, Trois-Rivières, 3351 Boulevard des Forges, CP 500, Québec G9A 5H7, Canada *Corresponding author. Email: jean-jacques.frenette@uqtr.ca ABSTRACT: While estuarine turbidity maxima (ETM) are commonly known for their high biological productivity, the high abundances of primary producers in these light-limited environments have long been questioned. In the St. Lawrence River ETM, we performed sampling cruises during August and October 2006 to test the hypothesis that advection of upstream algae is responsible for high phytoplankton biomass within the ETM. The ETM was situated at the freshwater end of the estuary, where salinity ranges from 0.06 to 1.10. This abrupt peak in turbidity (up to 89.9 and 49.5 nephelometer turbidity units [NTU] during August and October, respectively) coincides with peak chlorophyll a concentrations (54.8 and 22.9 µg l–1 during August and October, respectively); surface and depth concentrations were similar in the ETM and upstream, where the water column was vertically mixed. These biomasses represented an increase of >1 order of magnitude compared to upstream and downstream sites, while no growth proximal factor such as light or nutrients could explain this pattern. Sulfur-stable isotopic ratios from planktonic algae in the ETM differed from those of local periphyton, but corresponded to those of attached algae grown upstream in freshwater. Phytoplankton community structures were similar throughout the salinity gradient, and the vast majority of identified algae corresponded to genera common to freshwater, ETM and downstream environments. This study provides evidence that the observed peak in phytoplankton biomass within the ETM is largely due to high inputs of phytoplankton from upstream freshwater, rather than to local growth. KEY WORDS: Estuary · Turbidity · Light · Phytoplankton · Advection · Sulfur-stable isotopes Full text in pdf format PreviousNextCite this article as: Lapierre JF, Frenette JJ (2008) Advection of freshwater phytoplankton in the St. Lawrence River estuarine turbidity maximum as revealed by sulfur-stable isotopes. Mar Ecol Prog Ser 372:19-29. https://doi.org/10.3354/meps07685 Export citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 372. Online publication date: December 09, 2008 Print ISSN: 0171-8630; Online ISSN: 1616-1599 Copyright © 2008 Inter-Research.
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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 | 0.001 |
| Science and technology studies | 0.001 | 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) | 0.001 | 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".