Is the Gelatinous Matrix of Nassellaria (Radiolaria) a Strategy for Coping With Oligotrophy?
Bibliographic record
Abstract
Radiolaria are heterotrophic protists abundant in the world's oceans, playing important roles in biogeochemical cycles. Some host photosynthetic algae, contributing to primary production. Such mixotrophic behaviour is believed to explain their success in oligotrophic waters, notably Collodaria, exclusively mixotrophic radiolarians within a gelatinous matrix. Yet, understanding of Radiolaria ecology is limited to direct observations, as they have so far withstood reproduction in culture and lack genome data. Sampling oligotrophic California Current revealed abundant, rarely observed Nassellaria of the genus Phlebarachnium, characterised to live within a gelatinous matrix. Phylogenetic reconstruction of ribosomal DNA suggests that distantly related Nassellaria lineages independently developed the ability to produce a gelatinous matrix ~150 million years ago. By matching physical samples with genetic data, we identified these rarely observed organisms in global datasets, revealing their affinity for oligotrophic conditions. Co-occurrence networks showed distinct biogeography patterns for gelatinous matrix-forming Radiolaria compared to those without. Results suggest the matrix might be an adaptation to oligotrophic waters, increasing the effective volume, favouring prey capture, and creating a larger microenvironment for symbionts, thus promoting ecological success in nutrient-depleted waters. This study advances our understanding of the adaptation of poorly known eukaryotic groups, specifically when evolution occurs independently across lineages.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| 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) | 0.000 | 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 teacher head, 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".