Heme b quotas are low in Southern Ocean phytoplankton
Heme is the iron-containing prosthetic group of hemoproteins, and is thus required for photosynthesis, respiration and nitrate reduction in marine phytoplankton. Here we report concentrations of heme b in Southern Ocean phytoplankton and contrast our findings with those in coastal species. The conce...
Published in: | Marine Ecology Progress Series |
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Language: | English |
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ftsouthampton:oai:eprints.soton.ac.uk:380840 2023-08-27T04:12:09+02:00 Heme b quotas are low in Southern Ocean phytoplankton Gledhill, Martha Gerringa, Loes J.A. Laan, Patrick Timmermans, Klaas R. 2015 https://eprints.soton.ac.uk/380840/ English eng Gledhill, Martha, Gerringa, Loes J.A., Laan, Patrick and Timmermans, Klaas R. (2015) Heme b quotas are low in Southern Ocean phytoplankton. Marine Ecology Progress Series, 532, 29-40. (doi:10.3354/meps11345 <http://dx.doi.org/10.3354/meps11345>). Article PeerReviewed 2015 ftsouthampton https://doi.org/10.3354/meps11345 2023-08-03T22:21:11Z Heme is the iron-containing prosthetic group of hemoproteins, and is thus required for photosynthesis, respiration and nitrate reduction in marine phytoplankton. Here we report concentrations of heme b in Southern Ocean phytoplankton and contrast our findings with those in coastal species. The concentration of particulate heme b (pmol l-1) observed at the end of the exponential growth phase was related to the concentration of dissolved iron in the culture media. Small Southern Ocean phytoplankton species (<6 µm in diameter) had heme b quotas <1 µmol mol-1 carbon, the lowest yet reported for marine phytoplankton. Heme b was also depleted in these species with respect to chlorophyll a. We calculated the amount of carbon accumulated per mole of heme b per second in our cultures (heme growth efficiency, HGE) and found that small Southern Ocean species can maintain growth rates, even while heme b content is reduced. Small Southern Ocean phytoplankton can thus produce more particulate carbon than larger Southern Ocean or small coastal species at equivalent iron concentrations. Combining primary productivity and heme b concentrations reported for the open ocean, we found that HGE in natural populations was within the range of our laboratory culture results. HGE was also observed to be higher at open ocean stations characterized by low iron concentrations. Our results suggest that low heme b quotas do not necessarily result in reduced growth and that marine phytoplankton can optimize iron use by manipulating the intracellular hemoprotein pool. Article in Journal/Newspaper Southern Ocean University of Southampton: e-Prints Soton Southern Ocean Marine Ecology Progress Series 532 29 40 |
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Open Polar |
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University of Southampton: e-Prints Soton |
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ftsouthampton |
language |
English |
description |
Heme is the iron-containing prosthetic group of hemoproteins, and is thus required for photosynthesis, respiration and nitrate reduction in marine phytoplankton. Here we report concentrations of heme b in Southern Ocean phytoplankton and contrast our findings with those in coastal species. The concentration of particulate heme b (pmol l-1) observed at the end of the exponential growth phase was related to the concentration of dissolved iron in the culture media. Small Southern Ocean phytoplankton species (<6 µm in diameter) had heme b quotas <1 µmol mol-1 carbon, the lowest yet reported for marine phytoplankton. Heme b was also depleted in these species with respect to chlorophyll a. We calculated the amount of carbon accumulated per mole of heme b per second in our cultures (heme growth efficiency, HGE) and found that small Southern Ocean species can maintain growth rates, even while heme b content is reduced. Small Southern Ocean phytoplankton can thus produce more particulate carbon than larger Southern Ocean or small coastal species at equivalent iron concentrations. Combining primary productivity and heme b concentrations reported for the open ocean, we found that HGE in natural populations was within the range of our laboratory culture results. HGE was also observed to be higher at open ocean stations characterized by low iron concentrations. Our results suggest that low heme b quotas do not necessarily result in reduced growth and that marine phytoplankton can optimize iron use by manipulating the intracellular hemoprotein pool. |
format |
Article in Journal/Newspaper |
author |
Gledhill, Martha Gerringa, Loes J.A. Laan, Patrick Timmermans, Klaas R. |
spellingShingle |
Gledhill, Martha Gerringa, Loes J.A. Laan, Patrick Timmermans, Klaas R. Heme b quotas are low in Southern Ocean phytoplankton |
author_facet |
Gledhill, Martha Gerringa, Loes J.A. Laan, Patrick Timmermans, Klaas R. |
author_sort |
Gledhill, Martha |
title |
Heme b quotas are low in Southern Ocean phytoplankton |
title_short |
Heme b quotas are low in Southern Ocean phytoplankton |
title_full |
Heme b quotas are low in Southern Ocean phytoplankton |
title_fullStr |
Heme b quotas are low in Southern Ocean phytoplankton |
title_full_unstemmed |
Heme b quotas are low in Southern Ocean phytoplankton |
title_sort |
heme b quotas are low in southern ocean phytoplankton |
publishDate |
2015 |
url |
https://eprints.soton.ac.uk/380840/ |
geographic |
Southern Ocean |
geographic_facet |
Southern Ocean |
genre |
Southern Ocean |
genre_facet |
Southern Ocean |
op_relation |
Gledhill, Martha, Gerringa, Loes J.A., Laan, Patrick and Timmermans, Klaas R. (2015) Heme b quotas are low in Southern Ocean phytoplankton. Marine Ecology Progress Series, 532, 29-40. (doi:10.3354/meps11345 <http://dx.doi.org/10.3354/meps11345>). |
op_doi |
https://doi.org/10.3354/meps11345 |
container_title |
Marine Ecology Progress Series |
container_volume |
532 |
container_start_page |
29 |
op_container_end_page |
40 |
_version_ |
1775355985404100608 |