Publication Abstracts
Lam et al. 2020
Lam, P.J., M. Heller, , J. Moffett, and K. Buck, 2020: Unexpected source and transport of iron from the deep Peru Margin. ACS Earth Space Chem., 4, no. 7, 977-992, doi:10.1021/acsearthspacechem.0c00066.
Iron is the most important micronutrient in the ocean, but the nature and magnitude of its sources and sinks to the ocean are poorly constrained. Here we assess our understanding of the sources and sinks of iron in margin environments by synthesizing observations from the U.S. GEOTRACES GP16 Eastern Tropical Pacific Zonal Transect (EPZT) cruise near the Peru margin. GP16 observations showed elevated dissolved iron (dFe) concentrations along the margin, but a larger westward plume of dFe at slope depths (1000-3000 m) in oxygenated waters, rather than at shelf depths (100-300 m) in oxygen deficient waters. We examine the potential explanations for this unexpected observation. Multiple tracers from GP16 suggest that sediment resuspension was important at slope depths, which would lead to enhanced benthic flux of dFe above what was previously measured. The difference in the apparent persistence and penetration of shelf vs slope plumes of dFe into the interior of the ocean likely results from faster removal rates of the shelf dFe compared to slope dFe. DFe sourced from the shelf was almost entirely in the dFe(II) form, whereas dFe sourced from the slope was almost entirely in the dFe(III) form. Although benthic dFe(II) diffuses into oxygen deficient overlying waters, there is still oxidation of dFe(II), which precipitates to particulate Fe(III). In contrast, the slope plume appears to persist in a stabilized dFe(III) form. We hypothesize that sediment porewaters with moderate organic carbon delivery to sediments and shallow oxygen penetration are especially good sources of persistent dFe to the water column.
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BibTeX Citation
@article{la07500f,
author={Lam, P. J. and Heller, M. and Lerner, P. and Moffett, J. and Buck, K.},
title={Unexpected source and transport of iron from the deep Peru Margin},
year={2020},
journal={ACS Earth and Space Chemistry},
volume={4},
number={7},
pages={977--992},
doi={10.1021/acsearthspacechem.0c00066},
}
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RIS Citation
TY - JOUR ID - la07500f AU - Lam, P. J. AU - Heller, M. AU - Lerner, P. AU - Moffett, J. AU - Buck, K. PY - 2020 TI - Unexpected source and transport of iron from the deep Peru Margin JA - ACS Earth Space Chem. JO - ACS Earth and Space Chemistry VL - 4 IS - 7 SP - 977 EP - 992 DO - 10.1021/acsearthspacechem.0c00066 ER -
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