Temporal variation in the structure of intertidal assemblages following the removal of sewage
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 222:51-62 (2001) - doi:10.3354/meps222051 Temporal variation in the structure of intertidal assemblages following the removal of sewage P. Archambault1,*, K. Banwell2, A. J. Underwood1 1Centre for Research on Ecological Impacts of Coastal Cities, Marine Ecology Laboratories A11, University of Sydney, Sydney, New South Wales 2006, Australia 2New South Wales Department of Environmental Health, North Sydney, New South Wales 2059, Australia *Present address: Regional Oceans and Environment Branch, Fisheries and Oceans Canada, Institut Maurice-Lamontagne, 850, Route de la Mer, CP 1000, Mont-Joli, Québec G5H 3Z4, Canada. E-mail: archambaultp@dfo-mpo.gc.ca ABSTRACT: Following the closure of 2 outfalls, changes in the number of species and abundance of intertidal organisms at 2 decommissioned outfalls were compared with control (sewage outfalls that remained in operation) and reference (natural) areas. Two intertidal levels (mid- and low-shore) were sampled 5 times over 2 yr following the closure of these outfalls. It was proposed that the number of species would increase and the abundance of green algae would decrease through time at the decommissioned outfalls, while no noticeable changes in the number of species and the abundance of green algae were predicted at the reference and control locations. The 4 outfalls (2 decommissioned and 2 controls) were analysed separately with an asymmetrical ANOVA to identify differences between the outfall and the average of their 2 respective reference locations. Non-metric multi-dimensional scaling ordination using Bray-Curtis similarity was used to identify differences between outfalls and reference locations in the structure of the assemblages at the 2 heights on the shore. During the first (6 mo after closure) and second sampling period, fewer species and greater abundance of green algae were observed at every outfall than at their respective reference locations in low-shore areas. In the subsequent sampling periods, the number of species at the decommissioned outfalls increased through time while there were consistently fewer species at the control outfalls. The opposite pattern was observed for the abundance of green algae (i.e., decreases through time at the decommissioned outfalls). Assemblages at control outfalls never clustered with their reference locations. At midshore levels, no pattern was observed at any sampling date. Furthermore, at the first time of sampling, the number of species was not smaller at the outfalls than at reference locations. These results suggest that sewage outfalls have little impact on the number of midshore species. The results of univariate analysis were similar to those from multivariate analyses. Assemblages of species in low-shore areas at the decommissioned outfalls were different from those at reference locations at the first sampling date, but became more similar by the last sampling date. Some exceptions were observed at the site closest to the point of discharge. Again no differences in abundances of organisms were observed at any time for any outfall. The results showed a recovery of the benthic assemblages in the low-intertidal zone after the closure of 2 sewage outfalls. Furthermore, this study supports the importance of using more than 1 reference and control areas to measure recovery of a site without ambiguity. KEY WORDS: Sewage outfalls · Recovery · Human disturbance · Species richness · Green ephemeral algae · Benthic assemblage · Experimental design Full text in pdf format PreviousNextExport citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 222. Online publication date: November 05, 2001 Print ISSN: 0171-8630; Online ISSN: 1616-1599 Copyright © 2001 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 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 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".