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A physical estimate of new production in the equatorial Pacific along 150°W
Author(s) -
Carr MaryElena,
Lewis Marlon R.,
Kelley Dan,
Jones Burton
Publication year - 1995
Publication title -
limnology and oceanography
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.7
H-Index - 197
eISSN - 1939-5590
pISSN - 0024-3590
DOI - 10.4319/lo.1995.40.1.0138
Subject(s) - nitrate , photic zone , new production , upwelling , zonal and meridional , flux (metallurgy) , advection , chemistry , atmospheric sciences , environmental science , oceanography , nutrient , phytoplankton , geology , physics , organic chemistry , thermodynamics
New production was estimated for the equatorial Pacific by quantifying the supply of nitrate into the euphotic zone. The turbulent flux of nitrate, estimated by assuming gradient transport and by direct measurements of dissipation and nitrate concentration along a cross‐equatorial transect, was maximum (1–3 mmol m −3 d −1 ) at 0° and 1°S. Poleward of the equatorial region, there was little vertical diffusion of nitrate (< 10 −3 mmol m −2 d −1 ). An estimate was made of the two‐dimensional advective balance of nitrate between upwelling and the meridional divergence in the equatorial region. The net supply of nitrate into the euphotic zone (vertical supply minus meridional loss) was 4.3 mmol m −2 d −1 between 1°N and 1°S; between 5°N and 5°S, it was 1.9 mmol m −2 d −1 . The total supply of nitrate was larger than the concurrently measured incorporation of nitrate into particles but was comparable to the integrated local rate of nitrate disappearance. The discrepancy between new production estimated from physical supply or from nitrate disappearance and that estimated from nitrate incorporation into particles suggests that uptake by small cells (< 1 µ m), dissolved organic N, or both play an important role in the equatorial region.