Decoupling light harvesting, electron transport and carbon fixation during prolonged darkness supports rapid recovery upon re-illumination in the Arctic diatom Chaetoceros neogracilis

Type Article
Date 2019
Language English
Author(s) Lacour ThomasORCID1, 2, 3, Morin Philippe-Israël1, 2, Sciandra Théo1, 2, Donaher Natalie4, Campbell Douglas A.4, Ferland Joannie1, 2, Babin Marcel1, 2
Affiliation(s) 1 : Takuvik Joint International Laboratory, CNRS (France) & ULaval (Canada), Département de BiologieUniversité LavalQuébec, Canada
2 : Takuvik Joint International Laboratory, CNRS (France) & ULaval (Canada), Département de BiologieUniversité LavalQuébec, Canada
3 : IFREMER, Physiol & Biotechnol Algae LabsNantes Cedex 03, France
4 : Department of BiologyMount Allison UniversitySackville, Canada
Source Polar Biology (0722-4060) (Springer Science and Business Media LLC), 2019 , Vol. 42 , N. 10 , P. 1787-1799
DOI 10.1007/s00300-019-02507-2
WOS© Times Cited 14
Keyword(s) Arctic microalgae, Polar night, Diatom, Darkness, Photosynthesis, Growth rate, Temperature
Abstract

During winter in the Arctic marine ecosystem, diatoms have to survive long periods of darkness caused by low sun elevations and the presence of sea ice covered by snow. To better understand how diatoms survive in the dark, we subjected cultures of the Arctic diatom Chaetoceros neogracilis to a prolonged period of darkness (1 month) and to light resupply. Chaetoceros neogracilis was not able to grow in the dark but cell biovolume remained constant after 1 month in darkness. Rapid resumption of photosynthesis and growth recovery was also found when the cells were transferred back to light at four different light levels ranging from 5 to 154 µmol photon m−2 s−1. This demonstrates the remarkable ability of this species to re-initiate growth over a wide range of irradiances even after a prolonged period in the dark with no apparent lag period or impact on survival. Such recovery was possible because C. neogracilis cells preserved their Chl a content and their light absorption capabilities. Carbon fixation capacity was down-regulated (ninefold dark decrease in PCm) much more than was the photochemistry in PSII (2.3-fold dark decrease in ETRm). Rubisco content, which remained unchanged after one month in the dark, was not responsible for the decrease in PCm. The decrease in PSII activity was partially related to the induction of sustained non-photochemical quenching (NPQ) as we observed an increase in diatoxanthin content after one month in the dark.

Full Text
File Pages Size Access
13 1 MB Access on demand
6 935 KB Access on demand
Author's final draft 39 1 MB Open access
Top of the page

How to cite 

Lacour Thomas, Morin Philippe-Israël, Sciandra Théo, Donaher Natalie, Campbell Douglas A., Ferland Joannie, Babin Marcel (2019). Decoupling light harvesting, electron transport and carbon fixation during prolonged darkness supports rapid recovery upon re-illumination in the Arctic diatom Chaetoceros neogracilis. Polar Biology, 42(10), 1787-1799. Publisher's official version : https://doi.org/10.1007/s00300-019-02507-2 , Open Access version : https://archimer.ifremer.fr/doc/00499/61066/