Size independent selective filtration of ultraplankton by hexactinellid glass sponges
Bibliographic record
Abstract
AME Aquatic Microbial Ecology Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsSpecials AME 45:181-194 (2006) - doi:10.3354/ame045181 Size independent selective filtration of ultraplankton by hexactinellid glass sponges Gitai Yahel1,*, Dafne I. Eerkes-Medrano1,3, Sally P. Leys2 1Department of Biology, University of Victoria, PO Box 3020 Stn CSC, Victoria, British Columbia V8W 3N5, Canada 2Department of Biological Sciences, CW 405, Department of Biological Sciences, University of Alberta, Edmonton, Alberta T6G 2E9, Canada 3Present address: Department of Zoology, Oregon State University, Corvallis, Oregon 97331-2914, USA *Email: yahel@uvic.ca ABSTRACT: Selective feeding by flagellate and ciliate protists is important in shaping microbial communities in pelagic habitats. While less is known of predation on microbial communities in benthic habitats, the abundance and high filtering capacity of sponges suggests that they are key grazers. We studied the feeding preferences of two of the most common glass sponges of North-East Pacific fjords, Rhabdocalyptus dawsoni and Aphrocallistes vastus. Sponges were maintained in large darkened tanks supplied with running seawater from the nearby fjord. The water inhaled and exhaled by the sponges was simultaneously sampled and analyzed using a flow cytometer. Both sponges showed a similar (but not identical) feeding pattern, efficiently removing up to 99% of the most abundant bacterial cells, whereas clays, silt, and 'debris' particles were expelled into the exhaled water. Filtration efficiencies were maximal for the relatively large and rare eukaryotic algae (3 to 5 µm, 86 ± 9%) and for small non-photosynthetic bacteria (<0.4 µm, 89 ± 10%), while intermediate sized non-photosynthetic bacteria characterized by higher nucleic acid content were efficiently removed in February (92 ± 3%) when overall plankton concentration was low, but not in July (28 ± 16%). The intermediate sized photosynthetic prokaryote Synechococcus (1.1 to 1.5 µm) was also less preferred. Detailed analysis of the ultrastructure of the glass sponge filtration apparatus argues against possible 'by-pass' routes. We suggest that selective filtration involves individual processing, recognition, sorting, and transport of each particle through the sponges' syncytial tissue. Selective grazing by glass sponges, like their pelagic protozoan counterparts, could be an important mechanism shaping microbial communities in the detrital food web of North-East Pacific fjords. KEY WORDS: Selective feeding · Filtration · Aphrocallistes vastus · Rhabdocalyptus dawsoni Full text in pdf format PreviousNextExport citation RSS - Facebook - Tweet - linkedIn Cited by Published in AME Vol. 45, No. 2. Online publication date: November 24, 2006 Print ISSN: 0948-3055; Online ISSN: 1616-1564 Copyright © 2006 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) | 0.002 | 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".