CO2 and vitamin B12 interactions determine bioactive trace metal requirements of a subarctic Pacific diatom.
Phytoplankton growth can be limited by numerous inorganic nutrients and organic growth factors. Using the subarctic diatom Attheya sp. in culture studies, we examined how the availability of vitamin B(12) and carbon dioxide partial pressure (pCO(2)) influences growth rate, primary productivity, cellular iron (Fe), cobalt (Co), zinc (Zn) and cadmium (Cd) quotas, and the net use efficiencies (NUEs) of these bioactive trace metals (mol C fixed per mol cellular trace metal per day). Under B(12)-replete conditions, cells grown at high pCO(2) had lower Fe, Zn and Cd quotas, and used those trace metals more efficiently in comparison with cells grown at low pCO(2). At high pCO(2), B(12)-limited cells had ~50% lower specific growth and carbon fixation rates, and used Fe ~15-fold less efficiently, and Zn and Cd ~3-fold less efficiently, in comparison with B(12)-replete cells. The observed higher Fe, Zn and Cd NUE under high pCO(2)/B(12)-replete conditions are consistent with predicted downregulation of carbon-concentrating mechanisms. Co quotas of B(12)-replete cells were ∼5- to 14-fold higher in comparison with B(12)-limited cells, suggesting that >80% of cellular Co of B(12)-limited cells was likely from B(12). Our results demonstrate that CO(2) and vitamin B(12) interactively influence growth, carbon fixation, trace metal requirements and trace metal NUE of this diatom. This suggests the need to consider complex feedback interactions between multiple environmental factors for this biogeochemically critical group of phytoplankton in the last glacial maximum as well as the current and future changing ocean.
Department of Biological Sciences, University of Southern California, 3616 Trousdale Pkwy., Los Angeles, CA 90089, USA. andrewlk@usc.edu
Andrew L
AL
King
Sergio A
SA
Sañudo-Wilhelmy
Karine
K
Leblanc
David A
DA
Hutchins
Feixue
F
Fu
D002244:Carbon / Q000378:metabolism; D002245:Carbon Dioxide / Q000378:metabolism; D017377:Diatoms / Q000254:growth & development / Q000378:metabolism*; D017753:Ecosystem; D008670:Metals / Q000378:metabolism; D010140:Pacific Ocean; D010839:Phytoplankton / Q000378:metabolism*; D012623:Seawater / Q000469:parasitology*; D014805:Vitamin B 12 / Q000378:metabolism
D008670:Metals; D002245:Carbon Dioxide; D002244:Carbon; D014805:Vitamin B 12
Nature. 2005 May 5;435(7038):42
15875011
Nature. 2009 Jan 22;457(7228):467-70
19037243
Nature. 2001 May 3;411(6833):66-9
11333977
J Phycol. 1969 Mar;5(1):64-7
27097254
Biochem J. 2009 May 1;419(3):681-8
19200059
Nature. 2007 Nov 22;450(7169):545-8
17994008
Nature. 2004 Oct 7;431(7009):689-92
15470428
Trends Biochem Sci. 2004 May;29(5):243-9
15130560
J Biol Chem. 2003 Oct 17;278(42):41148-59
12869542
Nature. 2005 Nov 3;438(7064):90-3
16267554
Plant Physiol. 2000 May;123(1):345-52
10806251
Proc Natl Acad Sci U S A. 2010 Nov 30;107(48):20756-61
21068377
Science. 2010 Feb 5;327(5966):676-9
20075213
J Biol Chem. 2006 Dec 29;281(52):40461-72
17082184
Proc Natl Acad Sci U S A. 2000 Apr 25;97(9):4627-31
10781068