TY - JOUR

T1 - Estimating iron and aluminum removal rates in the eastern equatorial Pacific Ocean using a box model approach

A1 - Palacz,Artur P.

A1 - Chai,Fei

A1 - Dugdale,Richard C.

A1 - Measures,Christopher I.

A1 - david nelson,Michael R. Landry

AU - Palacz,Artur P.

AU - Chai,Fei

AU - Dugdale,Richard C.

AU - Measures,Christopher I.

AU - david nelson,Michael R. Landry

PB - Pergamon

PY - 2011

Y1 - 2011

N2 - Iron limitation plays an important role in maintaining the high-nitrate low-chlorophyll (HNLC) condition in the equatorial upwelling zone. The rate and depth of upwelling control Fe supply to the euphotic zone. This study constrains the transport fluxes and budget of two trace metals, Fe and Al, in the upper ocean. They are co-delivered to the eastern equatorial Pacific surface waters via the Equatorial Undercurrent and upwelling but show distinct biogeochemical cycling processes.We combine the results of the in situ measurements of dissolved Fe and Al (dFe and dAl) with the modeled velocity fields to calculate the physical fluxes. The model calculations are evaluated with the conservation of heat, volume transport, NO3 and Si(OH)4 budgets for the equatorial Pacific. The vertical flux due to upwelling provides averaged dFe and dAl supply rates of 1.45μmolm−2d−1 and 11.51μmolm−2d−1, respectively. The sum of the net physical fluxes in the eastern equatorial Pacific for dFe and dAl are 0.41μmolm−2d−1 and 2.77μmolm−2d−1, respectively. These estimates are equal to the net biological and chemical removal rates of dFe and dAl. The calculated dFe:C net removal ratio is in the range of 3-9μmol:mol, which agrees with most other estimates. This suggests that the majority of net dFe removal is due to biological uptake in the upper water column.The results of this box model approach illustrate the usefulness of combining the modeled outputs and in situ measurements, which provide additional constraints on Fe transport and cycling in the equatorial Pacific and possibly other HNLC regions.

AB - Iron limitation plays an important role in maintaining the high-nitrate low-chlorophyll (HNLC) condition in the equatorial upwelling zone. The rate and depth of upwelling control Fe supply to the euphotic zone. This study constrains the transport fluxes and budget of two trace metals, Fe and Al, in the upper ocean. They are co-delivered to the eastern equatorial Pacific surface waters via the Equatorial Undercurrent and upwelling but show distinct biogeochemical cycling processes.We combine the results of the in situ measurements of dissolved Fe and Al (dFe and dAl) with the modeled velocity fields to calculate the physical fluxes. The model calculations are evaluated with the conservation of heat, volume transport, NO3 and Si(OH)4 budgets for the equatorial Pacific. The vertical flux due to upwelling provides averaged dFe and dAl supply rates of 1.45μmolm−2d−1 and 11.51μmolm−2d−1, respectively. The sum of the net physical fluxes in the eastern equatorial Pacific for dFe and dAl are 0.41μmolm−2d−1 and 2.77μmolm−2d−1, respectively. These estimates are equal to the net biological and chemical removal rates of dFe and dAl. The calculated dFe:C net removal ratio is in the range of 3-9μmol:mol, which agrees with most other estimates. This suggests that the majority of net dFe removal is due to biological uptake in the upper water column.The results of this box model approach illustrate the usefulness of combining the modeled outputs and in situ measurements, which provide additional constraints on Fe transport and cycling in the equatorial Pacific and possibly other HNLC regions.

U2 - 10.1016/j.dsr2.2010.08.012

DO - 10.1016/j.dsr2.2010.08.012

JO - Deep-Sea Research. Part 2: Topical Studies in Oceanography

JF - Deep-Sea Research. Part 2: Topical Studies in Oceanography

SN - 0967-0645

IS - 3-4

VL - 58

SP - 311

EP - 324

ER -