TY - JOUR
T1 - Planktic foraminifera iodine/calcium ratios from plankton tows
AU - Winkelbauer, Helge A.
AU - Hoogakker, Babette A. A.
AU - Chance, Rosie J.
AU - Davis, Catherine V.
AU - Anthony, Christopher J.
AU - Bischoff, Juliane
AU - Carpenter, Lucy J.
AU - Chenery, Simon R. N.
AU - Hamilton, Elliott M.
AU - Holdship, Philip
AU - Peck, Victoria L.
AU - Poulton, Alex J.
AU - Stinchcombe, Mark C.
AU - Wishner, Karen F.
N1 - Funding Information:
This work was supported by a James Watt Scholarship awarded to HW. BH acknowledges support from UKRI Future Leaders Grant MR/S034293/1 and UK Natural Environment Research Council (NERC) grant NE/I020563/1. RC and LC profited from NERC grant NE/N009983/1 (Iodide in the ocean:distribution and impact on iodine flux and ozone loss) and NE/W00027X/1 (Iodine sea-air emissions and atmospheric impacts in a changing world (I-SEA)). Collection of the foraminifera specimens (by the MOCNESS net) in the Eastern Tropical Pacific OMZ during two research cruises was funded by National Science Foundation grant OCE-1459243 (PIs were Seibel, Wishner, and Roman). United States National Science Foundation OCE-1851589 to CD was used to support the isolation of foraminifera from MOCNESS tows in the Eastern Tropical North Pacific. The Benguela Cruise “COMICS” was funded by NERC with the codes NE/M020835/1 and NE/M020835/2. VP benefited from the UK Ocean Acidification research programme which was funded by the Department for Environment, Food and Rural Affairs, the NERC and the Department of Energy and Climate Change (NE/H017267/1, NE/H017097/1). Acknowledgments
Funding Information:
This work was supported by a James Watt Scholarship awarded to HW. BH acknowledges support from UKRI Future Leaders Grant MR/S034293/1 and UK Natural Environment Research Council (NERC) grant NE/I020563/1. RC and LC profited from NERC grant NE/N009983/1 (Iodide in the ocean:distribution and impact on iodine flux and ozone loss) and NE/W00027X/1 (Iodine sea-air emissions and atmospheric impacts in a changing world (I-SEA)). Collection of the foraminifera specimens (by the MOCNESS net) in the Eastern Tropical Pacific OMZ during two research cruises was funded by National Science Foundation grant OCE-1459243 (PIs were Seibel, Wishner, and Roman). United States National Science Foundation OCE-1851589 to CD was used to support the isolation of foraminifera from MOCNESS tows in the Eastern Tropical North Pacific. The Benguela Cruise “COMICS” was funded by NERC with the codes NE/M020835/1 and NE/M020835/2. VP benefited from the UK Ocean Acidification research programme which was funded by the Department for Environment, Food and Rural Affairs, the NERC and the Department of Energy and Climate Change (NE/H017267/1, NE/H017097/1).
Publisher Copyright:
Copyright © 2023 Winkelbauer, Hoogakker, Chance, Davis, Anthony, Bischoff, Carpenter, Chenery, Hamilton, Holdship, Peck, Poulton, Stinchcombe and Wishner.
PY - 2023/2/2
Y1 - 2023/2/2
N2 - Planktic foraminifera test iodine to calcium ratios represent an emerging proxy method to assess subsurface seawater oxygenation states. Several core-top studies show lower planktic foraminifera I/Ca in locations with oxygen depleted subsurface waters compared to well oxygenated environments. The reasoning behind this trend is that only the oxidized species of iodine, iodate, is incorporated in foraminiferal calcite. The I/Ca of foraminiferal calcite is thought to reflect iodate contents in seawater. To test this hypothesis, we compare planktic foraminifera I/Ca ratios, obtained from plankton tows, with published and new seawater iodate concentrations from 1) the Eastern North Pacific with extensive oxygen depletion, 2) the Benguela Current System with moderately depleted oxygen concentrations, and 3) the well oxygenated North and South Atlantic. We find the lowest I/Ca ratios (0.07 µmol/mol) in planktic foraminifera retrieved from the Eastern North Pacific, and higher values for samples (up to 0.72 µmol/mol) obtained from the Benguela Current System and North and South Atlantic. The I/Ca ratios of plankton tow foraminifera from environments with well oxygenated subsurface waters, however, are an order of magnitude lower compared to core-tops from similarly well-oxygenated regions. This would suggest that planktic foraminifera gain iodine post-mortem, either when sinking through the water column, or during burial.
AB - Planktic foraminifera test iodine to calcium ratios represent an emerging proxy method to assess subsurface seawater oxygenation states. Several core-top studies show lower planktic foraminifera I/Ca in locations with oxygen depleted subsurface waters compared to well oxygenated environments. The reasoning behind this trend is that only the oxidized species of iodine, iodate, is incorporated in foraminiferal calcite. The I/Ca of foraminiferal calcite is thought to reflect iodate contents in seawater. To test this hypothesis, we compare planktic foraminifera I/Ca ratios, obtained from plankton tows, with published and new seawater iodate concentrations from 1) the Eastern North Pacific with extensive oxygen depletion, 2) the Benguela Current System with moderately depleted oxygen concentrations, and 3) the well oxygenated North and South Atlantic. We find the lowest I/Ca ratios (0.07 µmol/mol) in planktic foraminifera retrieved from the Eastern North Pacific, and higher values for samples (up to 0.72 µmol/mol) obtained from the Benguela Current System and North and South Atlantic. The I/Ca ratios of plankton tow foraminifera from environments with well oxygenated subsurface waters, however, are an order of magnitude lower compared to core-tops from similarly well-oxygenated regions. This would suggest that planktic foraminifera gain iodine post-mortem, either when sinking through the water column, or during burial.
KW - I/Ca
KW - oxygen concentration
KW - oxygen proxy
KW - planktic foraminifera
KW - plankton nets
UR - http://www.scopus.com/inward/record.url?scp=85148364086&partnerID=8YFLogxK
U2 - 10.3389/fmars.2023.1095570
DO - 10.3389/fmars.2023.1095570
M3 - Article
SN - 2296-7745
VL - 10
JO - Frontiers in Marine Science
JF - Frontiers in Marine Science
M1 - 1095570
ER -