Climate Change Impacts on Stoichiometry, Phytoplankton, and Zooplankton in Alpine Lake Food Webs
Bibliographic record
Abstract
The main hypothesis of this study was that warmer and drier conditions affect fishless alpine lakes by increasing (1) phosphorus (P)-availability, (2) P-limited autotrophs versus mixotrophic phytoflagellates, and (3) fast-growing P-limited cladocerans versus slower-growing nitrogen (N)-rich calanoid copepods. To test this hypothesis, I conducted (1) a spatial survey of 16 mountain lakes along 1016 m of elevation (summer water temperatures: 5–17°C) in Alberta; (2) a temporal survey of an alpine lake over 16 y (summer water temperatures: 3–14°C); and (3) a laboratory experiment using two alpine and montane plankton communities subjected to warming (10°C; 17°C) and increased dissolved organic carbon (DOC; +80%). In the lake survey, higher temperatures and decreased lake depth were inferred using structural equation modeling (SEM) to decrease dissolved N:P, which increased chlorophytes and cyanophytes relative to phytoflagellates. Warming suppressed large-bodied cladocerans (Daphnia middendorffiana) and calanoid copepods (Hesperodiaptomus arcticus) and increased small-bodied zooplankton taxa. Small copepods increased relative to small cladocerans; this decreased particulate C:P via increased P-recycling by copepods. In the temporal investigation, SEM revealed that decreased rain reduced flushing of dissolved P, which increased diatoms relative to phytoflagellates in Pipit Lake. Unlike the lake survey, more moderate warming increased D. middendorffiana, while H. arcticus increased with advanced ice-off. Thus, cladocerans increased relative to copepods, which increased particulate C:P via increased P-retention by zooplankton. In the experiment, warming and DOC additions together increased P-availability, which increased autotrophs and offset the negative direct effects of warming and DOC. Warming increased D. middendorffiana but suppressed H. arcticus. Particulate C:P increased with DOC additions and increased cladocerans relative to copepods. These findings partially supported my main hypothesis. Climate effects increased dissolved P-availability, thereby increasing autotrophs relative to phytoflagellates. Shorter-term warming (temporal survey and experiment) increased cladocerans relative to copepods, whereas longer-term warming (spatial survey) suppressed large-bodied zooplankton and increased small taxa. Particulate C:P varied with changes in cladocerans relative to copepods (via P-recycling) and increases in C-rich terrestrial inputs. Findings suggest climate change will increase primary productivity of alpine lakes over several decades by increasing P-availability, and decreasing grazing efficiency as copepods and smaller-bodied zooplankton supercede cladocerans.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
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 | 0.001 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.004 | 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".