Temporal and spatial patterns of zooplankton abundance and productivity in Lake Erie using an Optical Plankton Counter
Notice bibliographique
Résumé
Distributions of crustacean zooplankton in Lake Erie were examined in 1998 and 1999 with an Optical Plankton Counter (OPC). Chapter 1 provides a new calibration of the OPC for use in freshwater and contrasts it with a previously developed calibration. Chapter 2 provides the first ever reported use of an OPC to examine seasonal dynamics of freshwater zooplankton. I found higher crustacean abundance and biomass (2–3x) in the central basin than the eastern basin during both years. Seasonal peak abundance and biomass occurred during June 1998 in both basins however during 1999 the east basin peak was not observed until July. Spring samples were dominated by cyclopoid copepods which gave way to large numbers of cladocerans in June which were in turn replaced by copepods, mostly calanoid copepods, in the summer and fall in both basins. Although the early season cladoceran peak in abundance and biomass is consistent with historical patterns in the lake it appears that there has been a shift to smaller Bosmina species from the large Daphnia species that were common during 1983–1987. Seasonal production estimates derived from the OPC samples are consistent with independent estimates using the egg ratio technique and indicate much greater production in the central basin than in the east basin during 1998 and 1999. Chapter 3 provides an overview of three commonly used techniques for spatial data analysis (Autocorrelation, Spectral Analysis, Wavelets) and one new technique (Principal Coordinates of Neighbour Matrices). I tested each technique on simulated data sets consisting of simple known spatial structure, complex known spatial structure, and real data with unknown spatial structure. All methods were able to identify the simple structures when presented in isolation, however the autocorrelation technique was unable to identify small-scale structure when present along with larger scale structure. Chapter 4 examines spatial structure in crustacean zooplankton of Lake Erie. Zooplankton showed patchy distributions at all spatial scales ranging from 7.5m to 10 000m. Principal Coordinates of Neighbour Matrices (PCNM) analyses revealed that most predictable repeating structure in both zooplankton biomass and chlorophyll biomass was restricted to spatial scales in excess of 504m regardless of the time of year. At these scales structuring mechanisms are likely physical in nature and relate to broadscale circulation patterns. The ability of the PCNM model to describe spatial structure varied seasonally with the lowest amount of variability being explained during mid-summer (July cruises) in both years. Total variance increased with depth as zooplankton distributions became patchier. (Abstract shortened by UMI.)
Récupéré en direct depuis OpenAlex et désinversé. Les résumés ne sont pas conservés dans cette base de données : les index inversés représentent 8,6 Go des 9,3 Go de texte de la base, et le serveur dispose de 13 Go libres.
Comment cette classification a été obtenuedéplier
Prédiction machine sur la base complète
Imitation des enseignantsNi prévalence calibrée, ni vérité terrain. Validation humaine à venir. Le volet Gemma est une étiquette directe du modèle pour chaque travail de la base, lue sur la notice réduite au titre. Le volet Codex est un classifieur appris des 10 348 étiquettes directes de Codex et calibré sur les taux pondérés de l'échantillon; les champs sans appui suffisant ne portent aucun appel Codex. Le mode candidate est l'union des deux volets; le consensus est leur intersection. Ces sorties portent le statut machine_predicted_unvalidated et ne sont pas des étiquettes humaines.
Scores du classifieur distillé par catégorie (deux têtes)
| Catégorie | Codex | Gemma |
|---|---|---|
| Métarecherche | 0,000 | 0,000 |
| Méta-épidémiologie (sens strict) | 0,000 | 0,000 |
| Méta-épidémiologie (sens large) | 0,000 | 0,000 |
| Bibliométrie | 0,001 | 0,001 |
| Études des sciences et des technologies | 0,000 | 0,000 |
| Communication savante | 0,000 | 0,000 |
| Science ouverte | 0,000 | 0,000 |
| Intégrité de la recherche | 0,000 | 0,000 |
| Charge utile insuffisante (le modèle a refusé de juger) | 0,000 | 0,000 |
Scores machine (provisoires)
Les deux têtes enseignantes du modèle étudiant, lues sur ce travail. Un score ordonne la base pour la relecture; il n'affirme jamais une catégorie, et le statut de validation accompagne chaque rangée tel quel.
Scores de référence d'un modèle non mature (critères de maturité non atteints, 7 itérations). Un score ordonne; il n'affirme jamais une catégorie.
score_only:v0-immature-baseline · tel quel depuis la passe de notation : score_only signifie que le nombre peut ordonner les travaux, et qu'aucune étiquette de catégorie n'en découleClassification
machine, non validéePrédiction automatique; un appel candidat d’une seule source (Gemma direct ou Codex distillé), pas un consensus.
Le détail, modèle par modèle et score par score, se trouve en fin de page sous « Comment cette classification a été obtenue ».