Effect of changing continuous iron input rates on a Southern Ocean algal assemblage
The upwelling of nutrients and iron (Fe) sustains biological production in much of the Southern Ocean. Using a shipboard natural community continuous culture system (Ecostat), we supplied a single added Fe concentration at two dilution rates chosen to examine the effects of variations in realistic g...
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Online Access: | https://doi.org/10.1016/j.dsr.2007.02.001 http://ecite.utas.edu.au/51419 |
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ftunivtasecite:oai:ecite.utas.edu.au:51419 2023-05-15T13:40:51+02:00 Effect of changing continuous iron input rates on a Southern Ocean algal assemblage Hare, CE DiTullio, GR Riseman, SF Crossley, AC Popels, LC Sedwick, PN Hutchins, DA 2007 https://doi.org/10.1016/j.dsr.2007.02.001 http://ecite.utas.edu.au/51419 en eng Pergamon-Elsevier Science Ltd http://dx.doi.org/10.1016/j.dsr.2007.02.001 Hare, CE and DiTullio, GR and Riseman, SF and Crossley, AC and Popels, LC and Sedwick, PN and Hutchins, DA, Effect of changing continuous iron input rates on a Southern Ocean algal assemblage, Deep Sea Research Part 1, 54, (5) pp. 732-746. ISSN 0967-0637 (2007) [Refereed Article] http://ecite.utas.edu.au/51419 Biological Sciences Ecology Marine and Estuarine Ecology (incl. Marine Ichthyology) Refereed Article PeerReviewed 2007 ftunivtasecite https://doi.org/10.1016/j.dsr.2007.02.001 2019-12-13T21:25:26Z The upwelling of nutrients and iron (Fe) sustains biological production in much of the Southern Ocean. Using a shipboard natural community continuous culture system (Ecostat), we supplied a single added Fe concentration at two dilution rates chosen to examine the effects of variations in realistic growth and loss rates on an Fe-limited algal community in the Antarctic Zone south of Australia. A parallel growout experiment provided "no-dilution" +Fe and -Fe controls. In the continuous flow experiment, phytoplankton biomass was lower and more constant throughout the incubation and major nutrients were never depleted. Nanophytoplankton abundance remained similar in both growout treatments, and therefore, growth of this group did not appear to be Fe-limited. The addition of Fe in a continuous fashion resulted in a community co-dominated by both small diatoms and nanophytoplankton. Increases in dilution rate favored diatom species that were smaller and faster-growing, as well as non-silicified algal groups. Particulate carbon (PC) to particulate nitrogen (PN) ratios increased above the Redfield ratio when Fe was added in a continuous fashion, while biogenic silica (BSi) to PC and PN ratios decreased 2-3 fold in the continuous flow experiment compared to the initial conditions and the parallel growout control experiment. Photosynthetic efficiency increased in the continuous flow treatments above the control but remained significantly lower than in the 1.4 nM Fe addition. The results of our shipboard continuous flow experiments are compared and contrasted with those of the mesoscale Southern Ocean Iron RElease Experiment (SOIREE) carried out at the same site. Our results suggest that increases in natural dilution rates (i.e. vertical turbulent diffusion) in polar Antarctic waters could shift the algal community towards smaller, faster-growing algal species, thus having a major effect on nutrient cycling and carbon export in the Southern Ocean. 2007 Elsevier Ltd. All rights reserved. Article in Journal/Newspaper Antarc* Antarctic Southern Ocean eCite UTAS (University of Tasmania) Antarctic Southern Ocean The Antarctic Deep Sea Research Part I: Oceanographic Research Papers 54 5 732 746 |
institution |
Open Polar |
collection |
eCite UTAS (University of Tasmania) |
op_collection_id |
ftunivtasecite |
language |
English |
topic |
Biological Sciences Ecology Marine and Estuarine Ecology (incl. Marine Ichthyology) |
spellingShingle |
Biological Sciences Ecology Marine and Estuarine Ecology (incl. Marine Ichthyology) Hare, CE DiTullio, GR Riseman, SF Crossley, AC Popels, LC Sedwick, PN Hutchins, DA Effect of changing continuous iron input rates on a Southern Ocean algal assemblage |
topic_facet |
Biological Sciences Ecology Marine and Estuarine Ecology (incl. Marine Ichthyology) |
description |
The upwelling of nutrients and iron (Fe) sustains biological production in much of the Southern Ocean. Using a shipboard natural community continuous culture system (Ecostat), we supplied a single added Fe concentration at two dilution rates chosen to examine the effects of variations in realistic growth and loss rates on an Fe-limited algal community in the Antarctic Zone south of Australia. A parallel growout experiment provided "no-dilution" +Fe and -Fe controls. In the continuous flow experiment, phytoplankton biomass was lower and more constant throughout the incubation and major nutrients were never depleted. Nanophytoplankton abundance remained similar in both growout treatments, and therefore, growth of this group did not appear to be Fe-limited. The addition of Fe in a continuous fashion resulted in a community co-dominated by both small diatoms and nanophytoplankton. Increases in dilution rate favored diatom species that were smaller and faster-growing, as well as non-silicified algal groups. Particulate carbon (PC) to particulate nitrogen (PN) ratios increased above the Redfield ratio when Fe was added in a continuous fashion, while biogenic silica (BSi) to PC and PN ratios decreased 2-3 fold in the continuous flow experiment compared to the initial conditions and the parallel growout control experiment. Photosynthetic efficiency increased in the continuous flow treatments above the control but remained significantly lower than in the 1.4 nM Fe addition. The results of our shipboard continuous flow experiments are compared and contrasted with those of the mesoscale Southern Ocean Iron RElease Experiment (SOIREE) carried out at the same site. Our results suggest that increases in natural dilution rates (i.e. vertical turbulent diffusion) in polar Antarctic waters could shift the algal community towards smaller, faster-growing algal species, thus having a major effect on nutrient cycling and carbon export in the Southern Ocean. 2007 Elsevier Ltd. All rights reserved. |
format |
Article in Journal/Newspaper |
author |
Hare, CE DiTullio, GR Riseman, SF Crossley, AC Popels, LC Sedwick, PN Hutchins, DA |
author_facet |
Hare, CE DiTullio, GR Riseman, SF Crossley, AC Popels, LC Sedwick, PN Hutchins, DA |
author_sort |
Hare, CE |
title |
Effect of changing continuous iron input rates on a Southern Ocean algal assemblage |
title_short |
Effect of changing continuous iron input rates on a Southern Ocean algal assemblage |
title_full |
Effect of changing continuous iron input rates on a Southern Ocean algal assemblage |
title_fullStr |
Effect of changing continuous iron input rates on a Southern Ocean algal assemblage |
title_full_unstemmed |
Effect of changing continuous iron input rates on a Southern Ocean algal assemblage |
title_sort |
effect of changing continuous iron input rates on a southern ocean algal assemblage |
publisher |
Pergamon-Elsevier Science Ltd |
publishDate |
2007 |
url |
https://doi.org/10.1016/j.dsr.2007.02.001 http://ecite.utas.edu.au/51419 |
geographic |
Antarctic Southern Ocean The Antarctic |
geographic_facet |
Antarctic Southern Ocean The Antarctic |
genre |
Antarc* Antarctic Southern Ocean |
genre_facet |
Antarc* Antarctic Southern Ocean |
op_relation |
http://dx.doi.org/10.1016/j.dsr.2007.02.001 Hare, CE and DiTullio, GR and Riseman, SF and Crossley, AC and Popels, LC and Sedwick, PN and Hutchins, DA, Effect of changing continuous iron input rates on a Southern Ocean algal assemblage, Deep Sea Research Part 1, 54, (5) pp. 732-746. ISSN 0967-0637 (2007) [Refereed Article] http://ecite.utas.edu.au/51419 |
op_doi |
https://doi.org/10.1016/j.dsr.2007.02.001 |
container_title |
Deep Sea Research Part I: Oceanographic Research Papers |
container_volume |
54 |
container_issue |
5 |
container_start_page |
732 |
op_container_end_page |
746 |
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1766141493187182592 |