Phenotypic plasticity of southern ocean diatoms: key to success in the sea ice habitat?

• Published in: PLoS ONE
• Main Authors: Olivia Sackett, Katherina Petrou, Brian Reedy, Adrian De Grazia, Ross Hill, Martina Doblin, John Beardall, Peter Ralph, Philip Heraud
• Format: Article in Journal/Newspaper
• Language: English
• Published: Public Library of Science (PLoS) 2013
• Subjects: Medicine; R; Science; Q; Southern Ocean; Sea ice
• Online Access: https://doi.org/10.1371/journal.pone.0081185; https://doaj.org/article/0a1ed534fe0243a3ba4b1bac00e24ed9

Diatoms are the primary source of nutrition and energy for the Southern Ocean ecosystem. Microalgae, including diatoms, synthesise biological macromolecules such as lipids, proteins and carbohydrates for growth, reproduction and acclimation to prevailing environmental conditions. Here we show that three key species of Southern Ocean diatom (Fragilariopsis cylindrus, Chaetoceros simplex and Pseudo-nitzschia subcurvata) exhibited phenotypic plasticity in response to salinity and temperature regimes experienced during the seasonal formation and decay of sea ice. The degree of phenotypic plasticity, in terms of changes in macromolecular composition, was highly species-specific and consistent with each species' known distribution and abundance throughout sea ice, meltwater and pelagic habitats, suggesting that phenotypic plasticity may have been selected for by the extreme variability of the polar marine environment. We argue that changes in diatom macromolecular composition and shifts in species dominance in response to a changing climate have the potential to alter nutrient and energy fluxes throughout the Southern Ocean ecosystem.