The effect of ambient N:P ratio and light on the nitrogen uptake and growth of select estuarine and oceanic dinoflagellates
Notice bibliographique
Résumé
Increasing frequency of harmful algal blooms (HABs) have been observed in eutrophic coastal ecosystems. The relationship between environmental factors (nutrients and light) and bloom-forming dinoflagellates were explored in this dissertation by both historical data analysis and laboratory experiments. The growth and nitrogen (N) acquisition of the HAB dinoflagellates Prorocentrum minimum, P. donghaiense, Karlodinium veneficum and Karenia brevis, were studied. It is hypothesized that estuarine species Prorocentrum spp. develops blooms in relative high N:P ratio water, while K. veneficum blooms near or lower than the Redfield ratio; these species will grow faster in the N:P ratio in which they develop blooms, even when these nutrients are not at limiting levels; Prorocentrum spp. preferentially take up more DIN in high DIN:DIP ratio water, while Karlodinium can better use other source of N in the low DIN water; low-light-adapted nitrogen acquisition by Prorocentrum spp. serves as an adaptive advantage to grow in low light waters. Historical data analysis showed that P. minimum generally develops blooms in high DIN, high N:P ratio, but turbid water in Chesapeake Bay, while K. veneficum blooms near or lower than the Redfield ratio, when DIN was depleted, but organic N sources were still available. Following these results, the effects of ambient N:P ratio and light on the growth and N acquisition of P. minimum and P. donghaiense were studied in both batch and continuous culture (turbidistat). Prorocentrum spp. were grown in a wide range of N:P ratios, and across a wide range of light intensities in turbidistat. Experiments to determine rates of N acquisition of different N sources were conducted using 15N tracer techniques at each N:P ratio and light treatment. However, in culture, the growth of the Prorocentrum species was not regulated by the ambient N:P ratio. When nutrients were sufficient, light, instead of ambient N:P ratio, regulated the algal ability to acquire N. The adaptive strategies of the two types of dinoflagellates, Prorocentrum spp. and Karlodinium/Karenia spp., are different. Prorocentrum minimum was shown to take up N in the dark. This light independent N uptake allows it to be more competitive in the relative low light near-shore water. Karlodinium/Karenia spp. apparently only takes up N in the light phase, but it can be mixotrophic and directly use organic sources, and thus may be more competitive after DIN was depleted. The Droop model, which describes the growth rate regulated by the cell quota, was used to interpret the relationship between N acquisition and the growth rate over the diel cycle of growth. Prorocentrum spp. continuously take up nitrogen at night to supplement the cell quota, and reaches the maximum cell quota at the beginning of light phase, when they reach the higher growth rate in a diel cycle. In eutrophic coastal systems (e.g., Chesapeake Bay), the ambient N:P ratio, as well as light may be critical factors for HAB growth. The dinoflagellates studied here have different adaptive strategies to grow in low light and to take advantage of high nutrients in the eutrophic waters. Prorocentrum spp. may dominant the high DIN water, while Karlodinium/Karenia spp. prefers organic nutrients.
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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) | 0,000 | 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 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 ».