Non-synergistic effects of water-soluble crude oil and enhanced ultraviolet-B radiation on a natural plankton assemblage
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 294:63-77 (2005) - doi:10.3354/meps294063 Non-synergistic effects of water-soluble crude oil and enhanced ultraviolet-B radiation on a natural plankton assemblage Peggy Sargian1, Behzad Mostajir2, Khaled Chatila3, Gustavo A. Ferreyra1,4, Émilien Pelletier1,*, Serge Demers1 1Institut des Sciences de la Mer de Rimouski (ISMER), Université du Québec à Rimouski, 310, Allée des Ursulines, Rimouski, Québec G5L 3A1, Canada2Réseaux Trophiques Pélagiques (GDR 2476) et Ecologie Microbienne des Milieux Aquatiques, UMR 5119 Écosystèmes Lagunaires, CNRS, Université Montpellier II, Case 093, 34095 Montpellier Cedex 5, France3Laboratoire dOcéanographie de Villefranche, CNRS-UPMC, BP 28, 06230 Villefranche-sur-Mer, France4Instituto Antártico Argentino (IAA), Cerrito 1248, Código Postal C1010AAZ Buenos Aires, Argentina *Corresponding author. Email: emilien_pelletier@uqar.qc.ca ABSTRACT: The present study demonstrates the effects of the water-soluble fraction (WSF) of a crude oil, enhanced ultraviolet-B radiation (UVBR: 280 to 320 nm), and the combination of WSF and enhanced UVBR on a natural plankton assemblage (<150 µm) isolated from the lower St. Lawrence Estuary. To study the separate and dual effects of WSF and UVBR, 12 microcosms (9 l) were immersed in the water column of larger mesocosms (polyethylene bags; 1800 l), providing 4 treatments, each in triplicate: (1) NUVBR + WSF (natural UVBR with WSF), (2) HUVBR + WSF (enhanced UVBR with WSF), (3) NUVBR (natural UVBR without WSF), and (4) HUVBR (enhanced UVBR without WSF). During 5 d we monitored the incident radiation, WSF and nutrient concentrations, abundance and production of heterotrophic bacteria and phytoplankton. Strong deleterious effects of WSF and lower effects of UVBR were observed on the phytoplankton assemblage, with a decrease in growth rates accompanied by an increase in mean cell size which reflected a perturbation of the cell division cycle. Using the NUVBR treatement as reference conditions, the above effects resulted in a reduction of 84, 79 and 60% of total abundance of the phytoplankton fraction <20 µm in the HUVBR + WSF, NUVBR + WSF and HUVBR treatments, respectively. Significant higher values of bacterial abundances were observed in the WSF-added treatments compared to NUVBR without WSF. However, bacterial thymidine incorporation exhibited diel variations, suggesting cumulative UVBR-induced DNA and/or PAH-induced DNA damages, and possible repair mechanisms with the co-occurrence of more available growth substrates from stressed phytoplankton. The absence of significant differences between both WSF-added treatments under the 2 different UVBR conditions suggests that there is no additive interaction between WSF and UVBR. This study provides therefore the first evidence of a non-synergistic interaction between both stresses, and suggests that UVBR-induced effects on marine microorganisms can be completely masked by the strong deleterious effects of soluble petroleum hydrocarbons. KEY WORDS: Ultraviolet radiation · Dissolved hydrocarbons · Non-synergistic effect · Phytoplankton · Bacteria Full text in pdf format PreviousNextExport citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 294. Online publication date: June 09, 2005 Print ISSN: 0171-8630; Online ISSN: 1616-1599 Copyright © 2005 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 | 0.000 |
| 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) | 0.001 | 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".