PIGI System
About
The Pressure of In-situ Gases Instrument (PIGI) (Fig. 1) is an autonomous, flow-through system capable of unattended O2 and N2 measurements from a continuous seawater supply line on research vessels, volunteer observing ships, or land-based field observatories. Using these measurements, it is possible to derive a tracer of net marine biological production, the biological O2 saturation anomaly (ΔO2/N2), and therefore derive estimates of net community production (NCP) at high resolution. The PIGI system has significant potential to greatly expand global coverage of NCP derivation.
The system consists of an Aanderaa Optode and Pro-Oceanus TDGP-mini Gas Tension Device (GTD). PIGI is controlled by custom-built LabVIEW software (for data logging, visualization and transmission via iridium), and is fully-contained within a Pelican case for easy transportation and installation. Calibration of the instruments is via discrete samples obtained from outflow of the instrument's chamber.
I have built three PIGI systems for concurrent deployments: one system is (currently) installed at the Hakai Institute Quadra Island Ecological Observatory on the central British Columbia coast (see Other current projects), while the others are routinely deployed on the CCGS J. P. Tully, and CCGS Amundsen for unsupervised data collection in the Subarctic Pacific and Canadian Arctic, respectively. A PIGI is routinely deployed on the Line P and La Perouse survey cruises for net community production estimation.
The system has undergone significant evolution. A version of PIGI (model 4.3, c. July 2020) is published in Oceanography (link to come), with a comprehensive assessment of the system, examples of field deployments, and full construction, assembly and deployment instructions. These files are duplicated below and are updated for system upgrades or further development.
The system consists of an Aanderaa Optode and Pro-Oceanus TDGP-mini Gas Tension Device (GTD). PIGI is controlled by custom-built LabVIEW software (for data logging, visualization and transmission via iridium), and is fully-contained within a Pelican case for easy transportation and installation. Calibration of the instruments is via discrete samples obtained from outflow of the instrument's chamber.
I have built three PIGI systems for concurrent deployments: one system is (currently) installed at the Hakai Institute Quadra Island Ecological Observatory on the central British Columbia coast (see Other current projects), while the others are routinely deployed on the CCGS J. P. Tully, and CCGS Amundsen for unsupervised data collection in the Subarctic Pacific and Canadian Arctic, respectively. A PIGI is routinely deployed on the Line P and La Perouse survey cruises for net community production estimation.
The system has undergone significant evolution. A version of PIGI (model 4.3, c. July 2020) is published in Oceanography (link to come), with a comprehensive assessment of the system, examples of field deployments, and full construction, assembly and deployment instructions. These files are duplicated below and are updated for system upgrades or further development.
Fig. 1. A schematic (a) and photographs (b-e) of the PIGI system. (c)-(e) show PIGI in her natural environment - collecting data in the field. The seawater flow paths are represented by the blue lines in (a). Labelled parts in (a)-(c) are: system inflow (1), debubbler (2), primary chamber (3), primary chamber flow meter (4), system outflow (5), TDGP-mini plenum (6), TDGP-mini GTD (7), Optode chamber (8), Optode with sensing foil shown in white (9), centrifugal pump (10), instruments flow meter (11), discrete sampling line (12) and Pelican case (13). In (d) and (e), the white, red and blue arrows show the locations of the electronics box, and a MIMS system.
System Details and Instructions
Overview:
Izett & Tortell, 2020. Oceanography. 33(2): https://doi.org/10.5670/oceanog.2020.214.
PIGI 4.3 (July 2020)
Same version published in Oceanography.
Izett & Tortell, 2020. Oceanography. 33(2): https://doi.org/10.5670/oceanog.2020.214.
PIGI 4.3 (July 2020)
Same version published in Oceanography.
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Construction and assembly instructions
Technical drawings Video instructions for cleaning Optode chamber: here |
Please refer here for potential future updates.
Software:
LabVIEW, Matlab, AutoIt and Solidworks files can be downloaded from GitHub: github.com/rizett/PIGI_system