MEPS 483:1-17 (2013)  -  doi:10.3354/meps10367

Heme b in marine phytoplankton and particulate material from the North Atlantic Ocean

David J. Honey1, Martha Gledhill1,*, Thomas S. Bibby1, François-Eric Legiret1, Nicola J. Pratt1, Anna E. Hickman1, Tracy Lawson2, Eric P. Achterberg

1Ocean and Earth Science, University of Southampton, National Oceanography Centre-Southampton, Southampton SO14 3ZH, UK
2Department of Biological Sciences, University of Essex, Wivenhoe Park, Colchester CO4 3SQ, UK
*Corresponding author. Email:

ABSTRACT: Concentrations of heme b, the iron-containing prosthetic group of many hemoproteins, were measured in 6 species of marine phytoplankton (Dunaliella tertiolecta, Emiliania huxleyi, Thalassiosira weissflogii, T. oceanica, Phaeodactylum tricornutum and Synechococcus sp. WH7803) that were subjected to variations in iron concentration. Changes in heme b in response to reduced light and nitrate were also examined for E. huxleyi and T. oceanica. Results from laboratory cultures were compared with heme b determined in particulate material in the North Atlantic. In cultures, heme b made up 18 ± 14% (SE) of the total iron pool. Reduced iron and nitrate concentrations resulted in a decreased intracellular heme b concentration, expressed as per mole carbon. Chlorophyll a (chl a) to heme b ratios in E. huxleyi and D. tertiolecta increased in response to limited light and nutrient availability, but slightly decreased or did not change in the diatoms and the cyanophyte Synechococcus sp. WH7803. The heme b:particulate organic carbon (POC) and chl a:heme b ratios in the North Atlantic were within the range observed in phytoplankton cultures. In the surface mixed layer, decreases in heme b:POC ratios were linked to decreases in nutrient concentrations. Chl a:heme b ratios increased with depth and were thus primarily affected by light availability. Relative relationships between heme b, chl a and POC in the North Atlantic likely represented a change in the ability of cells to undertake cellular processes driven by chl a (light harvesting) and heme b (e.g. electron transport) according to ambient light and nutrient conditions.

KEY WORDS: Hemoprotein · Iron · Electron transport · Cytochrome · Nutrient limitation · Celtic Sea

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Cite this article as: Honey DJ, Gledhill M, Bibby TS, Legiret FE and others (2013) Heme b in marine phytoplankton and particulate material from the North Atlantic Ocean. Mar Ecol Prog Ser 483:1-17

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