Effects of iron and light availability on phytoplankton photosynthetic properties in the Ross Sea - CEA - Commissariat à l’énergie atomique et aux énergies alternatives Accéder directement au contenu
Article Dans Une Revue Marine Ecology Progress Series Année : 2019

Effects of iron and light availability on phytoplankton photosynthetic properties in the Ross Sea

Résumé

Waters of the Southern Ocean are characterized by high macronutrient concentrations but limited availability of trace metals and light, often making it difficult for phytoplankton to achieve maximum growth rates. One strategy employed by Southern Ocean phytoplankton in culture to cope with low light and low dissolved iron (DFe) is to enhance light absorption by increasing their antenna size rather than the number of reaction centers, thereby reducing their Fe demand. Here we provide physiological evidence that natural populations of Southern Ocean phytoplankton employ a similar photoacclimation strategy to cope with low ambient DFe concentrations. During a research cruise to the Ross Sea in 2013-2014, we conducted 4 bioassay experiments in which we manipulated light and DFe concentrations and measured changes in phytoplankton biomass, growth rate, photosynthetic parameters, fluorescence parameters, and pigment composition. Phytoplankton responded strongly to DFe additions, exhibiting significantly higher biomass, growth rates, and photosynthetic competency. At low light, the maximum photosynthetic rate (P*max) was significantly reduced and the photosynthetic efficiency (α*) was unchanged compared to the high light treatment, regardless of phytoplankton species composition or DFe concentration. Our data suggest that Southern Ocean phytoplankton have evolved an Fe-saving strategy whereby they photoacclimate to low light by increasing their photosynthetic unit size, rather than photosynthetic unit number, even when DFe is available. It appears this Fe-saving strategy is characteristic of both Phaeocystis antarctica and diatoms, suggesting that it is a common adaptation among phytoplankton taxa that grow under Fe limitation in the Southern Ocean.
Fichier sous embargo
Fichier sous embargo
0 6 28
Année Mois Jours
Avant la publication
mercredi 27 novembre 2024
Fichier sous embargo
mercredi 27 novembre 2024
Connectez-vous pour demander l'accès au fichier

Dates et versions

cea-04307620 , version 1 (26-11-2023)

Identifiants

Citer

Anne-Carlijn Alderkamp, Gert L. Van Dijken, Kate E. Lowry, Kate M. Lewis, Hannah L. Joy-Warren, et al.. Effects of iron and light availability on phytoplankton photosynthetic properties in the Ross Sea. Marine Ecology Progress Series, 2019, 621, pp.33-50. ⟨10.3354/meps13000⟩. ⟨cea-04307620⟩
11 Consultations
1 Téléchargements

Altmetric

Partager

Gmail Facebook X LinkedIn More