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Automated measurements of biogeochemical and ecological cycles: results from the Southern Ocean Time Series

Automated measurements of biogeochemical and ecological cycles: results from the Southern Ocean Time Series
Tom Trull

Authors

Tom Trull
Institute for Marine and Antarctic Studies, University of Tasmania

Abstract

The IMOS Southern Ocean Time Series is located in the central Sub-Antarctic Zone, ~500km southwest of Tasmania. It consists of 3 moorings that measure air-sea exchanges, surface mixed layer biogeochemical processes, and deep sea sinking particle fluxes. These measurements provide information on processes important to climate, carbon cycling, and ocean productivity. This talk will give an overview of the SOTS facility, including opportunities for involvement. SOTS results emphasize the importance of accounting for seasonal cycles in assessments of climate and carbon cycle processes, and the application of advances in automated in-sensor applications for remote marine. As an example of new sensor approaches first time series for the Southern Ocean of hourly measurements of dissolved oxygen and nitrogen (from total gas tension) concentrations. Nitrogen was consistently supersaturated (100.8% - 102.9%), while oxygen was highly subsaturated in early spring (as low as 93.5%) and reached supersaturation during only 17% of the time series in mid-summer. These low oxygen levels emphasize the importance of the Subantarctic Zone in ventilating the upper limb of the overturning circulation, and that this process is incomplete. Using the nitrogen as a proxy for physical processes affecting gas budgets, we separated physical and biological contributions to the oxygen time series, and estimated a seasonal record of net community production (NCP). Almost all NCP occurred in short bursts in spring, in the presence of deep mixed layers as indicated by moored temperature sensors and nearby Argo float profiles, before ceasing at the start of summer in mid-December.

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Key dates

  • 11th June 2013
    Registrations close
  • 21st June 2013
    Registrations at the AAD open for staff
  • 24th June 2013
    Registrations at the venue open
  • 24th June 2013
    Conference commences
  • 26th June 2013
    Conference concludes

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This page was last modified on 5 September 2013.