Photoacclimation of the polar diatom Chaetoceros neogracilis at low temperature

Polar microalgae face two major challenges: 1- growing at temperatures (-1.7 to 5°C) that limit enzyme kinetics; and 2- surviving and exploiting a wide range of irradiance. The objective of this study is to understand the adaptation of an Arctic diatom to its environment by studying its ability to a...

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Bibliographic Details
Published in:PLOS ONE
Main Authors: Lacour, Thomas, Larivière, Jade, Ferland, Joannie, Morin, Philippe-Israël, Grondin, Pierre-Luc, Donaher, Natalie, Cockshutt, Amanda, Campbell, Douglas A., Babin, Marcel
Other Authors: Quigg, Antonietta, ArcticNet, Canada Excellence Research Chairs, Government of Canada, Canadian Network for Research and Innovation in Machining Technology, Natural Sciences and Engineering Research Council of Canada, Québec-Océan FRQNT strategic network
Format: Article in Journal/Newspaper
Language:English
Published: Public Library of Science (PLoS) 2022
Subjects:
Arctic
Online Access:http://dx.doi.org/10.1371/journal.pone.0272822
https://dx.plos.org/10.1371/journal.pone.0272822
Description
Summary:Polar microalgae face two major challenges: 1- growing at temperatures (-1.7 to 5°C) that limit enzyme kinetics; and 2- surviving and exploiting a wide range of irradiance. The objective of this study is to understand the adaptation of an Arctic diatom to its environment by studying its ability to acclimate to changes in light and temperature. We acclimated the polar diatom Chaetoceros neogracilis to various light levels at two different temperatures and studied its growth and photosynthetic properties using semi-continuous cultures. Rubisco content was high, to compensate for low catalytic rates, but did not change detectably with growth temperature. Contrary to what is observed in temperate species, in C . neogracilis , carbon fixation rate (20 min 14 C incorporation) equaled net growth rate (μ) suggesting very low or very rapid (<20 min) re-oxidation of the newly fixed carbon. The comparison of saturation irradiances for electron transport, oxygen net production and carbon fixation revealed alternative electron pathways that could provide energy and reducing power to the cell without consuming organic carbon which is a very limiting product at low temperatures. High protein contents, low re-oxidation of newly fixed carbon and the use of electron pathways alternative to carbon fixation may be important characteristics allowing efficient growth under those extreme environmental conditions.

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