Preprints
https://doi.org/10.5194/egusphere-2024-1508
https://doi.org/10.5194/egusphere-2024-1508
24 May 2024
 | 24 May 2024
Status: this preprint is open for discussion.

Temperature-enhanced effects of iron on Southern Ocean phytoplankton

Charlotte Eich, Mathijs van Manen, J. Scott P. McCain, Loay J. Jabre, Willem H. van de Poll, Jinyoung Jung, Sven B. E. H. Pont, Hung-An Tian, Indah Ardiningsih, Gert-Jan Reichart, Erin M. Bertrand, Corina P. D. Brussaard, and Rob Middag

Abstract. Iron (Fe) is a key limiting nutrient for Southern Ocean phytoplankton. Input of Fe into the Southern Ocean is projected to change due to global warming, yet the combined effects of a concurrent increase in temperature with Fe addition on phytoplankton growth and community composition are understudied. To improve our understanding of how Antarctic phytoplankton communities respond to Fe and enhanced temperature, we performed four full factorial onboard bioassays under trace metal clean conditions with phytoplankton communities from different regions of the Weddell and the Amundsen Seas in the Southern Ocean. Treatments consisted of a combined 2 nM Fe addition with 2 °C warming treatment (TF), compared to the single factor treatments of Fe addition at in-situ temperature (F), and non-Fe addition at + 2 °C (T) and at in-situ temperature (C). Temperature had limited effect by itself but boosted the positive response of the phytoplankton to Fe addition. Photosynthetic efficiency, phytoplankton abundances, and chlorophyll a concentrations typically increased (significantly) with Fe addition (F and/or TF treatments) and the phytoplankton community generally shifted from haptophytes to diatoms upon Fe addition. The < 20 µm phytoplankton fraction displayed population-specific growth responses, resulting in a pronounced shift in community composition and size distribution (mainly towards larger-sized phytoplankton) for the F and TF treatment. Such distinct enhanced impact of Fe supply with warming on Antarctic phytoplankton size, growth and composition will likely affect trophic transfer efficiency and ecosystem structure, with potential significance for the biological carbon pump.

Publisher's note: Copernicus Publications remains neutral with regard to jurisdictional claims made in the text, published maps, institutional affiliations, or any other geographical representation in this preprint. The responsibility to include appropriate place names lies with the authors.
Charlotte Eich, Mathijs van Manen, J. Scott P. McCain, Loay J. Jabre, Willem H. van de Poll, Jinyoung Jung, Sven B. E. H. Pont, Hung-An Tian, Indah Ardiningsih, Gert-Jan Reichart, Erin M. Bertrand, Corina P. D. Brussaard, and Rob Middag

Status: open (until 05 Jul 2024)

Comment types: AC – author | RC – referee | CC – community | EC – editor | CEC – chief editor | : Report abuse
  • RC1: 'Comment on egusphere-2024-1508', Anonymous Referee #1, 18 Jun 2024 reply
Charlotte Eich, Mathijs van Manen, J. Scott P. McCain, Loay J. Jabre, Willem H. van de Poll, Jinyoung Jung, Sven B. E. H. Pont, Hung-An Tian, Indah Ardiningsih, Gert-Jan Reichart, Erin M. Bertrand, Corina P. D. Brussaard, and Rob Middag
Charlotte Eich, Mathijs van Manen, J. Scott P. McCain, Loay J. Jabre, Willem H. van de Poll, Jinyoung Jung, Sven B. E. H. Pont, Hung-An Tian, Indah Ardiningsih, Gert-Jan Reichart, Erin M. Bertrand, Corina P. D. Brussaard, and Rob Middag

Viewed

Total article views: 248 (including HTML, PDF, and XML)
HTML PDF XML Total Supplement BibTeX EndNote
188 49 11 248 12 8 7
  • HTML: 188
  • PDF: 49
  • XML: 11
  • Total: 248
  • Supplement: 12
  • BibTeX: 8
  • EndNote: 7
Views and downloads (calculated since 24 May 2024)
Cumulative views and downloads (calculated since 24 May 2024)

Viewed (geographical distribution)

Total article views: 248 (including HTML, PDF, and XML) Thereof 248 with geography defined and 0 with unknown origin.
Country # Views %
  • 1
1
 
 
 
 
Latest update: 20 Jun 2024
Download
Short summary
Phytoplankton growth in the Southern Ocean (SO) is often limited by low iron (Fe) concentrations. Sea surface warming impacts Fe availability and can affect phytoplankton growth. We used Fe clean shipboard incubations to test how changes in Fe and temperature affect SO phytoplankton. Their abundances usually increased with Fe addition and temperature increase, with Fe being the major factor. These findings imply potential shifts in ecosystem structure, impacting food webs and elemental cycling.