Global Biogeochemical Cycles

High-resolution estimates of net community production and air-sea CO2 flux in the northeast Pacific

Authors

  • Deirdre Lockwood,

    Corresponding author
    1. School of Oceanography, University of Washington, Seattle, Washington, USA
      Corresponding author: D. Lockwood, School of Oceanography, University of Washington, Seattle, WA 98195, USA. (delockwood@gmail.com)
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  • Paul D. Quay,

    1. School of Oceanography, University of Washington, Seattle, Washington, USA
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  • Maria T. Kavanaugh,

    1. College of Earth, Ocean, and Atmospheric Sciences, Oregon State University, Corvallis, Oregon, USA
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  • Lauren W. Juranek,

    1. College of Earth, Ocean, and Atmospheric Sciences, Oregon State University, Corvallis, Oregon, USA
    2. Joint Institute for the Study of the Atmosphere and Ocean, University of Washington, Seattle, Washington, USA
    3. Pacific Marine Environmental Laboratory, NOAA, Seattle, Washington, USA
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  • Richard A. Feely

    1. Joint Institute for the Study of the Atmosphere and Ocean, University of Washington, Seattle, Washington, USA
    2. Pacific Marine Environmental Laboratory, NOAA, Seattle, Washington, USA
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Corresponding author: D. Lockwood, School of Oceanography, University of Washington, Seattle, WA 98195, USA. (delockwood@gmail.com)

Abstract

[1] Rates of net community production (NCP) and air-sea CO2 flux in the Northeast Pacific subarctic, transition zone and subtropical regions (22°N–50°N, 145°W–152°W) were determined on a cruise in August–September 2008 by continuous measurement of surface values of the ratio of dissolved oxygen to argon (O2/Ar) and the partial pressure of CO2 (pCO2). These estimates were compared with simultaneous measurements of sea surface temperature (SST), chlorophyll-a (chl-a), flow cytometry, and discrete surface nutrient concentrations. NCP and CO2 influx were greatest in the subarctic (45°N–50°N, 25.8 ± 4.6 and 4.1 ± 0.9 mmol C m−2 d−1) and northern transition zone (40°N–45°N, 17.1 ± 4.4 and 2.1 ± 0.5 mmol C m−2 d−1), with mean NCP ∼6–8× greater than mean CO2 invasion (error estimates reflect 1 σ confidence intervals). Contrastingly, the southern transition zone (32°N–40°N) and subtropics (22°N–32°N) had lower mean NCP (5.4 ± 1.8 and 8.1 ± 2.1 mmol C m−2 d−1, respectively) and mean CO2 efflux (3.0 ± 0.5 and 0.1 ± 0.0 mmol C m−2 d−1, respectively). In the subarctic and transition zone, NCP was highly correlated with surface chl-a and CO2 influx, indicating strong coupling between the biological pump and CO2 uptake. Meridional trends in our NCP estimates in the transition zone and subtropics were similar to those for integrated summertime NCP along the cruise track determined using an upper ocean climatological carbon budget.

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