Elevated temperature and decreased salinity both affect the biochemical composition of the Antarctic sea-ice diatom Nitzschia lecointei, but not increased pCO2

Areas in western Antarctica are experiencing rapid climate change, where ocean warming results in more sea ice melt simultaneously as oceanic CO2 levels are increasing. In this study, we have tested how increased temperature (from −1.8 to 3 °C) and decreased salinity (from 35 to 20 and 10) syne...

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Bibliographic Details
Published in:Polar Biology
Main Authors: Torstensson, Anders, Jiménez, Carlos, Nilsson, Anders K., Wulff, Angela
Format: Article in Journal/Newspaper
Language:English
Published: Uppsala universitet, Limnologi 2019
Subjects:
Fatty acids
PUFA
Salinity
TBARS
Temperature
pCO2
Ecology
Ekologi
Climate Research
Klimatforskning
Antarctic
The Antarctic
Antarc*
Antarctica
ice algae
Ocean acidification
Polar Biology
Sea ice
Online Access:http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-401774
https://doi.org/10.1007/s00300-019-02589-y
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Summary:Areas in western Antarctica are experiencing rapid climate change, where ocean warming results in more sea ice melt simultaneously as oceanic CO2 levels are increasing. In this study, we have tested how increased temperature (from −1.8 to 3 °C) and decreased salinity (from 35 to 20 and 10) synergistically affect the growth, photophysiology and biochemical composition of the Antarctic sea-ice diatom Nitzschia lecointei. In a separate experiment, we also addressed how ocean acidification (from 400 to 1000 µatm partial pressure of CO2) affects these key physiological parameters. Both positive and negative changes in specific growth rate, particulate organic carbon to particulate organic nitrogen ratio, chl a fluorescence kinetics, lipid peroxidation, carbohydrate content, protein content, fatty acid content and composition were observed when cells were exposed to warming and desalination. However, when cells were subjected to increased pCO2, only Fv/Fm, non-photochemical quenching and lipid peroxidation increased (by 3, 16 and 14%, respectively), and no other of the abovementioned biochemical properties were affected. These results suggest that changes in temperature and salinity may have more effects on the biochemical composition of N. lecointei than ocean acidification. Sea-ice algae are important component of polar food webs, and their nutritional quality may be affected as a result of altered environmental conditions due to climate change and sea ice melt.

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