Microbiomes of the Arctic carnivorous sponges <i>Chondrocladia grandis</i> and <i>Cladorhiza oxeata</i> suggest a specific, but differential involvement of bacterial associates
Bibliographic record
Abstract
While sponges are generally known to host a wide range of microbial associates, the composition and specificity of the microbial communities in carnivorous sponges are poorly understood. We used 16S rRNA gene data to examine and compare the bacterial communities associated with distinct anatomical regions of two carnivorous sponge species, Chondrocladia grandis and Cladorhiza oxeata, sampled from Baffin Bay and the Gulf of Maine (C. grandis only). The two sponge species hosted distinct bacterial communities, with taxonomic diversity being greater in C. grandis. Some bacterial taxa (including particular oligotypes) were consistently recovered in multiple host individuals from geographically distant sites, suggesting specificity. Within C. grandis, certain bacterial taxa were enriched in particular anatomical regions, suggesting functional roles in carnivorous sponge metabolism or other biological processes. Stable isotope analysis provided no evidence for methanotrophy in the sponges examined, but Gulf of Maine C. grandis might incorporate 13C-depleted carbon via the bacteria-mediated heterotrophic degradation of other hydrocarbons. Overall, our results demonstrate that the carnivorous sponge microbiome appears host species specific and stable, even over large geographical areas. The observed differences in bacterial community composition and diversity between C. grandis and C. oxeata may reflect differences in trophic adaptability, specialization, and overall reliance on associated bacteria.
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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 | 0.000 |
| 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".