Skip to Main content Skip to Navigation
Journal articles

Inorganic carbon uptake in a freshwater diatom, Asterionella formosa (Bacillariophyceae): from ecology to genomics

Abstract : Inorganic carbon availability can limit primary productivity and control species composition of freshwater phytoplankton. This is despite the presence of CO2-concentrating mechanisms (CCMs) in some species that maximize inorganic carbon uptake. We investigated the effects of inorganic carbon on the seasonal distribution, growth rates and photosynthesis of a freshwater diatom, Asterionella formosa, and the nature of its CCM using genomics. In a productive lake, the frequency of A. formosa declined with CO2 concentration below air-equilibrium. In contrast, CO2 concentrations at 2.5-times air-equilibrium did not increase growth rate, cell C-quota or the ability to remove inorganic carbon. A pH-drift experiment strongly suggested that HCO3− as well as CO2 could be used. Calculations combining hourly inorganic carbon concentrations in a lake with known CO2 and HCO3− uptake kinetics suggested that rates of photosynthesis of A. formosa would be approximately carbon saturated and largely dependent on CO2 uptake when CO2 was at or above air-equilibrium. However, during summer carbon depletion, HCO3− would be the major form of carbon taken up and carbon saturation will fall to around 30%. Genes encoding proteins involved in CCMs were identified in the nuclear genome of A. formosa. We found carbonic anhydrases from subclasses α, β, γ and θ, as well as solute carriers from families 4 and 26 involved in HCO3− transport, but no periplasmic carbonic anhydrase. A model of the components of the CCM and their location in A. formosa showed that they are more similar to Phaeodactylum tricornutum than to Thalassiosira pseudonana, two marine diatoms.
Document type :
Journal articles
Complete list of metadata

https://hal-amu.archives-ouvertes.fr/hal-03251911
Contributor : Brigitte Meunier-Gontero <>
Submitted on : Monday, June 7, 2021 - 1:53:48 PM
Last modification on : Tuesday, June 8, 2021 - 3:36:50 AM

File

 Restricted access
To satisfy the distribution rights of the publisher, the document is embargoed until : 2021-11-14

Please log in to resquest access to the document

Licence


Distributed under a Creative Commons Attribution - NonCommercial 4.0 International License

Identifiers

Collections

Citation

Stephen Maberly, Brigitte Gontero, Carine Puppo, Adrien Villain, Ilenia Severi, et al.. Inorganic carbon uptake in a freshwater diatom, Asterionella formosa (Bacillariophyceae): from ecology to genomics. Phycologia, International Phycological Society, 2021, pp.1-12. ⟨10.1080/00318884.2021.1916297⟩. ⟨hal-03251911⟩

Share

Metrics

Record views

35