In situ feeding and metabolism of glass sponges (Hexactinellida, Porifera) studied in a deep temperate fjord with a remotely operated submersible
Bibliographic record
Abstract
Glass sponges are conspicuous inhabitants of benthic communities in the cool waters of the Antarctic and north Pacific continental shelf. We used an ROV outfitted with a new device for simultaneous sampling of water inhaled and exhaled by the sponges to provide the first data on the nutritional ecology and metabolism of two glass sponge species in their natural deep‐water habitat (120–160 m). Aphrocallistes vastus and Rhabdocalyptus dawsoni were found to be mostly bacteriovores, removing up to 95% of the bacteria (median removal was 79% for both species) and heterotrophic protists (<10 µm) from the water they filter. The relatively scarce microbial cells were efficiently selected from a ‘soup’ of suspended clay and detritus particles (microorganisms accounted for ~1% of the total ambient suspended solids). Removal of planktonic microorganisms (2.2 ± 1.3 µmol carbon [C] C L −1 and 0.37 ± 0.17 µmol nitrogen [N] L −1 ) accounted for the entire total organic C uptake and ammonium excretion by both species, with no evidence for dissolved organic uptake. Similar results were obtained in laboratory experiments in which dissolved organic C was directly measured. Despite the massive siliceous sponge skeleton, silica uptake was below detection levels (0.28 µmol L −1 ), supporting previous suggestions of low growth rates in Hexactinellida. Reported mean sponge abundances of >1 individual m −2 indicate that the sponge filtering activity may significantly affect the deep microbial community and benthic‐pelagic mass exchange in some north‐east Pacific fjords.
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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 | 0.001 | 0.000 |
| Science and technology studies | 0.000 | 0.001 |
| 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".