Organic Complexation of Iron in the Eastern Tropical South Pacific: Results From US GEOTRACES Eastern Pacific Zonal Transect (GEOTRACES Cruise GP16)

Kristen N. Buck; Peter N. Sedwick; Bettina Sohst; Craig A. Carlson

doi:10.1016/j.marchem.2017.11.007

Organic Complexation of Iron in the Eastern Tropical South Pacific: Results From US GEOTRACES Eastern Pacific Zonal Transect (GEOTRACES Cruise GP16)

Kristen N. Buck, Peter N. Sedwick, Bettina Sohst, Craig A. Carlson

College of Marine Science

Research output: Contribution to journal › Article › peer-review

Abstract

Dissolved iron, organic iron-binding <a href="https://www.sciencedirect.com/topics/earth-and-planetary-sciences/ligand" title="Learn more about Ligand from ScienceDirect's AI-generated Topic Pages"> ligands </a> , and <a href="https://www.sciencedirect.com/topics/earth-and-planetary-sciences/organic-carbon" title="Learn more about Organic Carbon from ScienceDirect's AI-generated Topic Pages"> organic carbon </a> were determined in full water column depth profiles across the US GEOTRACES Eastern Pacific Zonal <a href="https://www.sciencedirect.com/topics/earth-and-planetary-sciences/transect" title="Learn more about Transect from ScienceDirect's AI-generated Topic Pages"> Transect </a> (GEOTRACES cruise GP16) in late 2013. Dissolved iron concentrations exhibited subsurface maxima associated with the <a href="https://www.sciencedirect.com/topics/earth-and-planetary-sciences/remineralization" title="Learn more about Remineralization from ScienceDirect's AI-generated Topic Pages"> remineralization </a> of <a href="https://www.sciencedirect.com/topics/chemistry/organic-matter" title="Learn more about Organic Matter from ScienceDirect's AI-generated Topic Pages"> organic matter </a> at the Peru shelf and with hydrothermal inputs from the East Pacific Rise. Iron-binding organic ligands are described as ligand classes based on defined ranges in conditional stability constants. The stronger L 1 -type ligands were measured in large excesses in surface and <a href="https://www.sciencedirect.com/topics/earth-and-planetary-sciences/intermediate-water" title="Learn more about Intermediate Water from ScienceDirect's AI-generated Topic Pages"> intermediate waters </a> , and these excesses were negatively correlated with Si*, a biogeochemical proxy for iron limited <a href="https://www.sciencedirect.com/topics/earth-and-planetary-sciences/diatom" title="Learn more about Diatom from ScienceDirect's AI-generated Topic Pages"> diatom </a> growth. These data suggest sources of strong iron-binding ligands from iron limitation of diatom communities, both locally and in waters originating from the Southern Ocean. Benthic sources of strong ligands were associated with new iron inputs from <a href="https://www.sciencedirect.com/topics/earth-and-planetary-sciences/hydrothermal-activity" title="Learn more about Hydrothermal Activity from ScienceDirect's AI-generated Topic Pages"> hydrothermal activity </a> at the East Pacific Rise and from bottom sediments. In contrast to most studies in the Atlantic basin but consistent with previous datasets from the Pacific, stronger L 1 ligands in this dataset were generally restricted to the upper water column and did not show large excesses through the water column. At depth, iron-binding ligands on GP16 were instead best described as L 2 and L 3 ligands. Concomitant decreases in excess L 1 , excess total ligands and <a href="https://www.sciencedirect.com/topics/earth-and-planetary-sciences/dissolved-organic-carbon" title="Learn more about Dissolved Organic Carbon from ScienceDirect's AI-generated Topic Pages"> dissolved organic carbon </a> suggest similar degradation pathways of these pools below the surface.

Original language	American English
Journal	Marine Chemistry
Volume	201
DOIs	https://doi.org/10.1016/j.marchem.2017.11.007
State	Published - Apr 20 2018

Keywords

Iron
Ligands
Chemical speciation
Dissolved organic carbon

Disciplines

Life Sciences

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https://doi.org/10.1016/j.marchem.2017.11.007

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@article{b48ec53d48ee4672b0f24c28edaeea7c,

title = "Organic Complexation of Iron in the Eastern Tropical South Pacific: Results From US GEOTRACES Eastern Pacific Zonal Transect (GEOTRACES Cruise GP16)",

abstract = " Dissolved iron, organic iron-binding ligands , and organic carbon were determined in full water column depth profiles across the US GEOTRACES Eastern Pacific Zonal Transect (GEOTRACES cruise GP16) in late 2013. Dissolved iron concentrations exhibited subsurface maxima associated with the remineralization of organic matter at the Peru shelf and with hydrothermal inputs from the East Pacific Rise. Iron-binding organic ligands are described as ligand classes based on defined ranges in conditional stability constants. The stronger L 1 -type ligands were measured in large excesses in surface and intermediate waters , and these excesses were negatively correlated with Si*, a biogeochemical proxy for iron limited diatom growth. These data suggest sources of strong iron-binding ligands from iron limitation of diatom communities, both locally and in waters originating from the Southern Ocean. Benthic sources of strong ligands were associated with new iron inputs from hydrothermal activity at the East Pacific Rise and from bottom sediments. In contrast to most studies in the Atlantic basin but consistent with previous datasets from the Pacific, stronger L 1 ligands in this dataset were generally restricted to the upper water column and did not show large excesses through the water column. At depth, iron-binding ligands on GP16 were instead best described as L 2 and L 3 ligands. Concomitant decreases in excess L 1 , excess total ligands and dissolved organic carbon suggest similar degradation pathways of these pools below the surface. ",

keywords = "Iron, Ligands, Chemical speciation, Dissolved organic carbon",

author = "Buck, {Kristen N.} and Sedwick, {Peter N.} and Bettina Sohst and Carlson, {Craig A.}",

year = "2018",

month = apr,

day = "20",

doi = "10.1016/j.marchem.2017.11.007",

language = "American English",

volume = "201",

journal = "Marine Chemistry",

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TY - JOUR

T1 - Organic Complexation of Iron in the Eastern Tropical South Pacific: Results From US GEOTRACES Eastern Pacific Zonal Transect (GEOTRACES Cruise GP16)

AU - Buck, Kristen N.

AU - Sedwick, Peter N.

AU - Sohst, Bettina

AU - Carlson, Craig A.

PY - 2018/4/20

Y1 - 2018/4/20

N2 - Dissolved iron, organic iron-binding ligands , and organic carbon were determined in full water column depth profiles across the US GEOTRACES Eastern Pacific Zonal Transect (GEOTRACES cruise GP16) in late 2013. Dissolved iron concentrations exhibited subsurface maxima associated with the remineralization of organic matter at the Peru shelf and with hydrothermal inputs from the East Pacific Rise. Iron-binding organic ligands are described as ligand classes based on defined ranges in conditional stability constants. The stronger L 1 -type ligands were measured in large excesses in surface and intermediate waters , and these excesses were negatively correlated with Si*, a biogeochemical proxy for iron limited diatom growth. These data suggest sources of strong iron-binding ligands from iron limitation of diatom communities, both locally and in waters originating from the Southern Ocean. Benthic sources of strong ligands were associated with new iron inputs from hydrothermal activity at the East Pacific Rise and from bottom sediments. In contrast to most studies in the Atlantic basin but consistent with previous datasets from the Pacific, stronger L 1 ligands in this dataset were generally restricted to the upper water column and did not show large excesses through the water column. At depth, iron-binding ligands on GP16 were instead best described as L 2 and L 3 ligands. Concomitant decreases in excess L 1 , excess total ligands and dissolved organic carbon suggest similar degradation pathways of these pools below the surface.

AB - Dissolved iron, organic iron-binding ligands , and organic carbon were determined in full water column depth profiles across the US GEOTRACES Eastern Pacific Zonal Transect (GEOTRACES cruise GP16) in late 2013. Dissolved iron concentrations exhibited subsurface maxima associated with the remineralization of organic matter at the Peru shelf and with hydrothermal inputs from the East Pacific Rise. Iron-binding organic ligands are described as ligand classes based on defined ranges in conditional stability constants. The stronger L 1 -type ligands were measured in large excesses in surface and intermediate waters , and these excesses were negatively correlated with Si*, a biogeochemical proxy for iron limited diatom growth. These data suggest sources of strong iron-binding ligands from iron limitation of diatom communities, both locally and in waters originating from the Southern Ocean. Benthic sources of strong ligands were associated with new iron inputs from hydrothermal activity at the East Pacific Rise and from bottom sediments. In contrast to most studies in the Atlantic basin but consistent with previous datasets from the Pacific, stronger L 1 ligands in this dataset were generally restricted to the upper water column and did not show large excesses through the water column. At depth, iron-binding ligands on GP16 were instead best described as L 2 and L 3 ligands. Concomitant decreases in excess L 1 , excess total ligands and dissolved organic carbon suggest similar degradation pathways of these pools below the surface.

KW - Iron

KW - Ligands

KW - Chemical speciation

KW - Dissolved organic carbon

UR - https://digitalcommons.usf.edu/msc_facpub/558

UR - https://doi.org/10.1016/j.marchem.2017.11.007

U2 - 10.1016/j.marchem.2017.11.007

DO - 10.1016/j.marchem.2017.11.007

M3 - Article

VL - 201

JO - Marine Chemistry

JF - Marine Chemistry

ER -

Organic Complexation of Iron in the Eastern Tropical South Pacific: Results From US GEOTRACES Eastern Pacific Zonal Transect (GEOTRACES Cruise GP16)

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