MEPS 550:39-51 (2016)  -  DOI: https://doi.org/10.3354/meps11732

A comparative study of iron and temperature interactive effects on diatoms and Phaeocystis antarctica from the Ross Sea, Antarctica

Zhi Zhu1,*, Kai Xu1,*, Feixue Fu1, Jenna L. Spackeen2, Deborah A. Bronk2, David A. Hutchins1,**

1Department of Biological Science, University of Southern California, Los Angeles, CA 90089, USA
2Department of Physical Sciences, Virginia Institute of Marine Science, College of William & Mary, PO Box 1346, Gloucester Point, VA 23062, USA
*Corresponding author:

ABSTRACT: In the future, temperature and iron availability are predicted to change in the coastal polynyas of Antarctica, which are the most biologically productive regions of the Southern Ocean. We examined the individual and combined effects of iron addition (+500 nM) and temperature increase (4°C) on Phaeocystis antarctica and several dominant diatom species isolated from the McMurdo Sound sector of the Ross Sea. Iron addition increased growth, carbon fixation, iron uptake rates, cellular carbon quota, and cell size of almost all tested species, while temperature increase only affected certain species. Concurrent increases in temperature and iron synergistically stimulated the growth rates of some species, particularly Pseudo-nitzschia subcurvata. The diversified responses of these phytoplankton to iron and temperature may help explain the current spatial and temporal distributions of diatoms and prymnesiophytes in the Ross Sea. In the future, potential temperature and iron increases may promote the growth of the diatoms Chaetoceros sp., Fragilariopsis cylindrus, and especially P. subcurvata. In contrast, growth rates of P. antarctica did not increase at higher temperatures, suggesting that a shift in community composition toward diatoms may occur under warmer conditions in this biologically and biogeochemically important Southern Ocean polynya region.


KEY WORDS: Antarctic · Global warming · Fe input · Phytoplankton community · Diatom · Phaeocystis · Pseudo-nitzschia


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Cite this article as: Zhu Z, Xu K, Fu F, Spackeen JL, Bronk DA, Hutchins DA (2016) A comparative study of iron and temperature interactive effects on diatoms and Phaeocystis antarctica from the Ross Sea, Antarctica. Mar Ecol Prog Ser 550:39-51. https://doi.org/10.3354/meps11732

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