Multi-scale variability in phytoplankton populations of the North Atlantic basin: from eddies to global change
Notice bibliographique
Résumé
The Continuous Plankton Recorder (CPR) survey has been deployed since 1931 to describe and analyze plankton variability in the North Atlantic and North Sea. This survey measures the presence and abundance of 437 phytoplankton and zooplankton taxa and provides an assessment of phytoplankton biomass, the Phytoplankton Colour Index (VCI). The diatoms and dinoflagellates are the two main phytoplankton groups identified by the CPR survey. The first part of this work provides insights into the space-time dynamics of phytoplankton communities through an analysis of diatom and dinoflagellate populations in the whole North Atlantic basin. Because the North Atlantic Ocean includes many different biotopes, the second part focuses on the mesoscale variability of phytoplankton species. The long-term fluctuations of the phytoplankton species are studied in the NW and in the NE Atlantic, the two best sampled areas of the CPR survey. In the NE Atlantic, the aim is to determine the contribution of the diatoms and dinoflagellates to the PCI, their fluctuations over 45 years of sampling and their geographical variations. Because local variability in environmental conditions is thought to play a dominant role in temporal fluctuations of phytoplankton biomass, the next part takes advantage to define small areas around the British Isles. This allowed me to study more precisely the processes influencing the long-term variation of phytoplankton assemblages. The North Atlantic Current transports water across the Northern basin of the Atlantic Ocean, along the shelf of Ireland and form the Norwegian current which corresponds to the inflow of oceanic waters into the Norwegian Sea and the North Sea. In this highly hydrodynamic region attention is focused on the fluctuations of plankton species in relation to the currents. The aim of this part is therefore to investigate the fluctuations of phytoplankton biomass, diatoms and dinoflagellates, their geographical distribution and abundance within the area and their relationship with physical processes. The intense hydrodynamic activity observed in the Northwestern Atlantic Shelves Province (NWCS) makes this region especially intriguing from the point of view of physical-biological interactions. The relationship between spatial and temporal structures of eddies (via Sea Surface Heights) and chlorophyll a (from the Sea-viewing Wide Field-of-view Sensor, Sea WiFS) was assessed along the Gulf Stream axis. In particular, the physical structures identified were followed and compared with phytoplankton distribution. In addition, the impact of the LSW changing flow along the Scotian Shelf and the influence of Gulf Stream rings along the George Bank is determined. This work demonstrated that changes are occurring in pelagic ecosystems at different temporal and spatial scales. These changes have been illustrated by the spatial variability induced by eddies and/or currents but also by the regional variability of the hydro-climatic processes, influencing in different ways Sea Surface Temperature, wind-regimes and mixing of local environments. Several different aspects of the North Atlantic Oscillations impact on pelagic ecosystems have been highlighted. In the northeast Atlantic, NA0 fluctuations imply changes in (i) SST in northern Europe, (ii) wind regimes, (iii) Atlantic Water inflow into the North Sea. In contrast, in the northwest Atlantic, the variations of NAO imply changes in (i) SST on the Scotian Shelf, (ii) coastal currents, and (iii) inflow of Labrador Sea Slope Water (LSSW) towards the Scotian Shelf and Georges Bank. These changes in environmental process impact phytoplankton production, abundance, spatial distribution, community structure phenology and ultimately would impact trophodynamics processes. It is, however, still difficult to explain unambiguously all the mechanisms that are involved in the control of the observed patterns.
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 distillée sur la base complète
Imitation des enseignantsNi prévalence calibrée, ni vérité terrain. Validation humaine à venir. Apprise à partir de 10 348 étiquettes directes de Codex et de 10 348 étiquettes directes de Gemma. Le mode candidate est l'union des têtes enseignantes seuillées; le consensus est leur intersection. Ces sorties portent le statut machine_predicted_unvalidated et ne sont ni des étiquettes humaines ni des étiquettes directes de modèles de pointe.
Scores Codex et Gemma par catégorie
| 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 | 0,000 | 0,000 |
| 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) | 0,002 | 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 tête enseignante, 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 ».