Morphological Variation in Acrosiphonia arcta (Codiolales, Chlorophyta) from Environmentally Different Habitats in Nova Scotia, Canada
Bibliographic record
Abstract
We characterized the morphological variation and algal species associations of the filamentous green alga, Acrosiphonia arcta (distinguishing it from its closely related sister genus Spongomorpha), in two contrasting environments in Nova Scotia, Canada. The habitats differed in seawater salinity and temperature (and fluctuations thereof), substratum, vertical position on the shore, wave exposure, turbidity, and diversity of macroalgae and macrofauna. Acrosiphonia arcta thalli exhibited distinct morphologies in the different environments. Thalli from the open-ocean Whitehead site (Atlantic coast) exhibited the typical A. arcta morphology of profuse, short, curved branches and rhizoids binding the filaments together to form hemispherical to spherical tufts. Thalli from the sheltered Pomquet Harbour Estuary (Gulf of St. Lawrence coast) consisted of matted clumps with extensive rhizoidal growth at the base but little branching otherwise. Acrosiphonia arcta was primarily associated with thick leathery and crustose (coralline) algae at Whitehead. In the Pomquet Harbour Estuary, a less stable habitat than Whitehead, sheet and filamentous algae were in greater abundance with A. arcta than at Whitehead. Damaged apical cells from thalli of both Pomquet and Whitehead A. arcta were able to regenerate new filamentous tips or to give rise to rhizoids, phenomena not previously documented for Acrosiphonia in North America. Morphological variation of A. arcta in different habitats points to its ability to respond to and persist in a wide range of abiotic (and possibly biotic) conditions, and helps to explain its seasonal dominance on the east and west coasts of North America.
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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 | 0.002 | 0.002 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.000 | 0.001 |
| 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".