Contrasting Photo-physiological Responses of the Haptophyte Phaeocystis Antarctica and the Diatom Pseudonitzschia sp. in the Ross Sea (Antarctica)

The Antarctic is a unique environment in which substantial variations in irradiance occur over a number of time scales, and as a result phytoplankton need to acclimate and adapt to these changes. We conducted field and laboratory manipulations in the Ross Sea, Antarctica to examine photophysiologica...

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Bibliographic Details
Published in:AIMS Geosciences
Main Authors: Tozzi, Sasha, Smith, Walker O., Jr.
Format: Text
Language:unknown
Published: W&M ScholarWorks 2017
Subjects:
PHYTOPLANKTON TAXA
SOUTHERN-OCEAN
FRAGILARIOPSIS-CYLINDRUS
CHLOROPHYLL FLUORESCENCE
LIGHT STRESS
IRON
GROWTH
PRYMNESIOPHYCEAE
PHOTOPHYSIOLOGY
PHOTOPROTECTION
Biological Sciences Peer-Reviewed Articles
Marine Biology
Antarctic
Ross Sea
Southern Ocean
The Antarctic
Antarc*
Antarctica
Online Access:https://scholarworks.wm.edu/vimsarticles/22
https://scholarworks.wm.edu/context/vimsarticles/article/1021/viewcontent/geosci_03_00142.pdf
Description
Summary:The Antarctic is a unique environment in which substantial variations in irradiance occur over a number of time scales, and as a result phytoplankton need to acclimate and adapt to these changes. We conducted field and laboratory manipulations in the Ross Sea, Antarctica to examine photophysiological differences between Phaeocystis antarctica and Pseudonitzschia sp. a diatom that commonly occurrs in the Ross Sea, since these are the two functional groups that dominate abundance and productivity. Both exhibited reduced quantum yields due to high irradiances. P. antarctica, a haptophyte, displays a distinct photophysiological response to irradiance when compared to diatoms. P. antarctica showed a rapid recovery from high light exposure, as indicated by the rapid return to initial, high quantum yields, in contrast to diatoms, which responded more slowly. Absorption cross sections were high in both forms, but those in P. antarctica were significantly higher. Both organisms recovered within 24 h to initial quantum yields, suggesting that high irradiance exposure does not have a permanent effect on these organisms. Among all micronutrient additions (iron, cobalt, zinc and vitamin B-12), only iron additions resulted in rapid impacts on quantum yields. Iron limitation also can result in reduced photosynthetic efficiency. Understanding these photophysiologial responses and the impact of oceanographic conditions provides constraints on modeling efforts of photosynthesis and primary productivity in the Antarctic.

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