Publication Date:
2018-07-17
Description:
Impacts of rising atmospheric CO2 concentrations
and increased daily irradiances from enhanced
surface water stratification on phytoplankton
physiology in the coastal Southern Ocean remain
still unclear. Therefore, in the two Antarctic diatoms
Fragilariopsis curta and Odontella weissflogii, the
effects of moderate and high natural solar radiation
combined with either ambient or future pCO2 on
cellular particulate organic carbon (POC) contents
and photophysiology were investigated. Results
showed that increasing CO2 concentrations had
greater impacts on diatom physiology than exposure
to increasing solar radiation. Irrespective of the
applied solar radiation regime, cellular POC quotas
increased with future pCO2 in both diatoms.
Lowered maximum quantum yields of
photochemistry in PSII (Fv/Fm) indicated a higher
photosensitivity under these conditions, being
counteracted by increased cellular concentrations of
functional photosynthetic reaction centers. Overall,
our results suggest that both bloom-forming
Antarctic coastal diatoms might increase carbon
contents under future pCO2 conditions despite
reduced physiological fitness. This indicates a
higher potential for primary productivity by the two
diatom species with important implications for the
CO2 sequestration potential of diatom communities
in the future coastal Southern Ocean.
Repository Name:
EPIC Alfred Wegener Institut
Type:
Article
,
isiRev
