Phagocytosis of microbial symbionts balances the carbon and nitrogen budget for the deep‐water boreal sponge <i>Geodia barretti</i>
Bibliographic record
Abstract
Abstract Geodia barretti is a massive nearly spherical sponge that forms dense assemblages on the continental shelf of the North Atlantic and the Norwegian Sea. We studied the metabolism of individual sponges collected using a remotely operated vehicle and maintained in large tanks with high volumes of unfiltered water brought from 160 m depth. We used direct methods (In‐Ex) to measure excurrent flow rates, oxygen removed, and carbon and nutrient flux through the sponges. G. barretti had very low specific filtration (0.26 mL min−1 mL−1 sponge tissue) and low respiration (5.34 ± 0.98 nmol O2 min−1 mL−1 sponge tissue; 8.44 ± 1.51 μmol O2 h−1 g C−1) rates in comparison to other sponges. A net release of nitrogen was detected as . Bacteria were removed from the water filtered with up to 99% efficiency, yet comprised only 5% of the sponges′ total carbon budget; the remainder consisted of dissolved organic carbon and detritus. High bacterial removal was aided by the presence of a tight gasket of cells that surrounds the collar of each choanocyte filter. A test for potential bypass canals showed removal of fluorescent microspheres until they were excreted 5–12 h after feeding. Electron micrographs showed active uptake of Escherichia coli “fed” to the sponge as well as phagocytosis of symbiont microbes by sponge cells in the mesohyl. These data provide the first comprehensive study of metabolism in a deep‐water high microbial abundance sponge.
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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".