Heme <i>b</i> distributions through the Atlantic Ocean: evidence for "anemic" phytoplankton populations

Louropoulou, Evangelia, Gledhill, Martha, Achterberg, Eric P, Browning, Thomas J, Honey, David J, Schmitz, Ruth A and Tagliabue, Alessandro ORCID: 0000-0002-3572-3634
(2020) Heme <i>b</i> distributions through the Atlantic Ocean: evidence for "anemic" phytoplankton populations. SCIENTIFIC REPORTS, 10 (1). 4551-.

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Heme b is an iron-containing cofactor in hemoproteins that participates in the fundamental processes of photosynthesis and respiration in phytoplankton. Heme b concentrations typically decline in waters with low iron concentrations but due to lack of field data, the distribution of heme b in particulate material in the ocean is poorly constrained. Here we report particulate heme b distributions across the Atlantic Ocean (59.9°N to 34.6°S). Heme b concentrations in surface waters ranged from 0.10 to 33.7 pmol L<sup>-1</sup> (median = 1.47 pmol L<sup>-1</sup>, n = 974) and were highest in regions with a high biomass. The ratio of heme b to particulate organic carbon (POC) exhibited a mean value of 0.44 μmol heme b mol<sup>-1</sup> POC. We identified the ratio of 0.10 µmol heme b mol<sup>-1</sup> POC as the cut-off between heme b replete and heme b deficient (anemic) phytoplankton. By this definition, we observed anemic phytoplankton populations in the Subtropical South Atlantic and Irminger Basin. Comparison of observed and modelled heme b suggested that heme b could account for between 0.17-9.1% of biogenic iron. Our large scale observations of heme b relative to organic matter provide further evidence of the impact of changes in iron supply on phytoplankton iron status across the Atlantic Ocean.

Item Type: Article
Uncontrolled Keywords: Phytoplankton, Iron, Heme, Water Pollutants, Biomass, Photosynthesis, Atlantic Ocean
Depositing User: Symplectic Admin
Date Deposited: 01 Jun 2020 09:17
Last Modified: 14 Oct 2023 11:36
DOI: 10.1038/s41598-020-61425-0
Related URLs:
URI: https://livrepository.liverpool.ac.uk/id/eprint/3089216