Gas exchange, dispersion, and biological productivity on the west Florida shelf: Results from a Lagrangian tracer study

Rik Wanninkhof, Gary Hitchcock, William J. Wiseman, Gabe Vargo, Peter B. Ortner, William Asher, David T. Ho, Peter Schlosser, Mary Lynn Dickson, Robert Masserini, Kent Fanning, Jia Zhong Zhang

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Abstract

A Lagrangian tracer study was performed on the west Florida shelf in April 1996 using deliberately injected trace gases. Although such studies have been performed previously, this work is the first where the deliberate tracers, in conjunction with carbon system parameters, are used to quantify changes in water column carbon inventories due to air-sea exchange and net community metabolism. The horizontal dispersion and the gas transfer velocity were determined over a period of 2 weeks from the change in both the concentrations and the concentration ratio of the two injected trace gases, sulfur hexafluoride (SF6) and helium-3 (3He). The second moment of the patch grew to 1.6 × 103 km2 over a period of 11 days. The gas transfer velocity, normalized to CO2 exchange at 20°C, was 8.4 cm hr-1 at an average wind speed, U10, of 4.4 m s-1 for the duration of the experiment, which is in good agreement with empirical estimates. Remineralization rates exceeded productivity, causing an increase in dissolved inorganic carbon of about 1 μmol kg-1 day-1 in the water column. During this period of senescence, 80% of the increase in inorganic carbon is attributed to community remineralization and 20% due to invasion of atmospheric CO2.

Original languageEnglish (US)
Article number97GL01757
Pages (from-to)1767-1770
Number of pages4
JournalGeophysical Research Letters
Volume24
Issue number14
DOIs
StatePublished - Jan 1 1997
Externally publishedYes

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ASJC Scopus subject areas

  • Geophysics
  • Earth and Planetary Sciences(all)

Cite this

Wanninkhof, R., Hitchcock, G., Wiseman, W. J., Vargo, G., Ortner, P. B., Asher, W., Ho, D. T., Schlosser, P., Dickson, M. L., Masserini, R., Fanning, K., & Zhang, J. Z. (1997). Gas exchange, dispersion, and biological productivity on the west Florida shelf: Results from a Lagrangian tracer study. Geophysical Research Letters, 24(14), 1767-1770. [97GL01757]. https://doi.org/10.1029/97GL01757