DOI: 10.21966/nkcy-8c07
title: High-resolution record of CO 2 content from October 2013 to December 2018 measured in seawater entering the Alutiiq Pride Shellfish Hatchery in Seward, Alaska, USA

description: The Alutiiq Pride Shellfish Hatchery in Seward, Alaska has been a site for shore-based and high-resolution measurement of seawater CO2 content since October 2013. Measurements of temperature, salinity, and CO2 partial pressure are made near-continuously from a seawater sample line with an intake 100 m from the hatchery and at a depth of 75 m in Resurrection Bay. The effort to collect these data is a collaboration between the Alutiiq Pride Shellfish Hatchery and the Hakai Institute with support from the Alaska Ocean Observing System via the project “Turning the Headlights on ‘High’: Improving an Ocean Acidification Observing System in Support of Pacific Coast Shellfish Growers” (http://www.nanoos.org/documents/announcements/msi-announcement-oa.pdf) that was jointly funded by IOOS and NOAA’s Ocean Acidification Program. CO2 data were collected using either a Sunburst Sensors SUPERCO2 system (October 13, 2013 to August 5, 2014) or a Burke-o-Lator pCO2/TCO2 analyzer (August 15, 2014 to December 20, 2018). Temperature and salinity data were collected using a Sea-Bird SBE 45 MicroTSG Thermosalinograph. The collection and analysis of these data are part of the Hakai Institute’s directive to advance the understanding of carbon cycling in northeast Pacific coastal settings with specific emphasis on ocean acidification. 

Cite as: Evans, W., J. Ramsay, C. Weekes, and J. Hetrick (2018). High-resolution record of CO2 content from October 2013 to December 2018 measured in seawater entering the Alutiiq Pride Shellfish Hatchery in Seward, Alaska, USA. Version 1.0. Hakai Institute. Dataset. [access date]. 

Type of Study: Continuous data record

Temporal Coverage: October 5, 2013 to December 20, 2018

Spatial Coverage: Seawater drawn from 75-m depth approximately 100 m from the Alutiiq Pride Shellfish Hatchery in Seward, Alaska; southcentral Alaska; 60.0992°N, 149.4428°W

Geographic Names: Resurrection Bay; southcentral Alaska; Gulf of Alaska; North Pacific Ocean

Location of organism collection: N/A

Platforms: Shore-side laboratory; Alutiiq Pride Shellfish Hatchery

Version: 1.0

Submission Date: January 9, 2019

Filename: APSHBoL_5mindata_submission

Column Header Information: (1) serial date number (SDN) (2) Microsoft Excel date (3) pCO2@equilibratorT (µatm) (4) NIST temp (°C) (5) YSI salinity (PSS-78) 

Variables:

Partial pressure of carbon dioxide 
Abbreviation: pCO2
Unit: µatm
Observation type: measurements from continuously flowing seawater stream
In-situ/Manipulation/Response variable: In situ observation 
Measured or calculated: calculated from measured CO2 mole fractions (xCO2) and ambient atmospheric pressure.
Sampling instrument: equilibrator
Analyzing instrument: Sunburst Sensors SUPERCO2 or Dakunalytics, LLC Burke-o-Lator (BoL) pCO2/TCO2 analyzer both with LI-COR LI-840A NDIR detectors
Detailed sampling and analyzing information: Seawater pCO2 data collected using the SUPERCO2 have been published previously (Evans, W., Mathis, J.T., Ramsay, J., and Hetrick, J. (2015). On the Frontline: Tracking Ocean Acidification in an Alaskan Shellfish Hatchery. PLoS One 10, e0130384.). pCO2 data collected using the BoL followed the methodology described in Evans, W., Pocock, K., Hare, A., Weekes, C., Hales, B., Jackson, J., Gurney-Smith, H., Mathis, J.T., Alin, S.R., and Feely, R.A. (2019). Marine CO2 Patterns in the Northern Salish Sea. Frontiers in Marine Science, doi: 10.3389/fmars.2018.00536. Using either system, pCO2 was calculated from corrected measurements of CO2 mixing ratio (xCO2). Seawater continuously flowed between 0.5 and 1 gpm first through a Sea-Bird SBE45 thermosalinograph and into the equilibrator. Carrier gas (marine air) was recirculated between the equilibrator from the electronics box of either the SUPERCO2 or BoL. Equilibrated carrier gas was then supplied to a non-dispersive infrared gas analyzer (LI-COR LI840A CO2/H2O) housed within the electronics box. Pressure and temperature were continuously measured in the equilibrator using a Honeywell ASCX Microstructure Pressure Sensor and a Minco Fast Response RTD, respectively. Equilibrated carrier gas, standard gases of known mixing ratio, and unaltered marine air were all plumbed to provide gas flow to the electronics box. These systems were controlled using National Instruments LabVIEW software run on Windows or Apple computers. The software controls data acquisition from the thermosalinograph, the pressure and temperature sensors, and the LI-COR; while also controlling Valco Instruments Co. Inc. (VICI) multi-port actuators that cycle between the gas streams plumbed to the electronics box. None of the gas streams were dried prior to analysis, and all measurements were made at either 0.5 or 1 Hz. The prescribed measurement scheme controlled by the software was to supply equilibrated carrier gas from the equilibrator to the LI-COR continuously for a set length of time (typically 720 minutes), then cycle the actuators to consecutively allow the standard gas streams and unaltered marine air to be measured for 90 s before returning to sample the carrier gas equilibrated with seawater xCO2. From each sequence of standard gas measurements, the final 20 s of data in the 120 s interval before the actuator changed position were used to construct calibration functions that were then interpolated in time between standard gas sequences. These functions were then used to calibrate the xCO2 measurements of seawater equilibrated carrier gas. Corrected seawater xCO2 was subsequently adjusted for under-pressurization in the equilibrator using the ratio of equilibrator to vented LI-COR cell pressure, and then converted to pCO2 using atmospheric pressure measured by the LI-COR. The seawater pCO2, temperature and salinity data were quality controlled, and then bin-averaged in 5-min interval bins. No correction from equilibrator temperature to in situ temperature was applied to this dataset.
Replicate information: N/A
Standardization description: xCO2 calibration functions developed during periodic sequential analysis of gas standards of known concentration
Standardization frequency: variable, typically every 720 minutes.
CRM manufacturer: formerly Scott-Marin, Inc., now Praxair Distribution Inc
Poison name: N/A
Poison volume: N/A
Poison correction: N/A
Uncertainty: 2 ppm for calibrated xCO2; ~2 µatm for pCO2
Quality flag convention: no quality flag applied
Method reference: Hales, B., D. Chipman, and T. Takahashi (2004), High-frequency measurements of partial pressure and total concentration of carbon dioxide in seawater using microporous hydrophobic membrane contactors, Limnology and Oceanography: Methods, 2, 356-364; Pierrot, D., C. Neill, K. Sullivan, R. Castle, R. Wanninkhof, H. Lüger, T. Johannessen, A. Olsen, R. A. Feely, and C. E. Cosca (2009), Recommendations for autonomous underway pCO2 measuring systems and data-reduction routines, Deep Sea Research Part II: Topical Studies in Oceanography, 56(8-10), 512-522, doi:10.1016/j.dsr2.2008.12.005; Evans, W., Mathis, J.T., Ramsay, J., and Hetrick, J. (2015). On the Frontline: Tracking Ocean Acidification in an Alaskan Shellfish Hatchery. PLoS One 10, e0130384; Evans, W., Pocock, K., Hare, A., Weekes, C., Hales, B., Jackson, J., Gurney-Smith, H., Mathis, J.T., Alin, S.R., and Feely, R.A. (2019). Marine CO2 Patterns in the Northern Salish Sea. Frontiers in Marine Science, doi: 10.3389/fmars.2018.00536.
Researcher name: Wiley Evans
Researcher institution: Hakai Institute

Seawater temperature 
Abbreviation: SST
Unit: °C, ITS-90 scale
Observation type: measurements from continuously flowing seawater stream
In-situ/Manipulation/Response variable: In situ observation 
Measured or calculated: measured
Sampling instrument: N/A
Analyzing instrument: Sea-Bird SBE 45 MicroTSG Thermosalinograph
Detailed sampling and analyzing information: 1 Hz data captured using National Instruments LabVIEW software on an iMac computer
Replicate information: N/A
Standardization description: N/A
Standardization frequency: N/A
CRM manufacturer: N/A
Poison name: N/A
Poison volume: N/A
Poison correction: N/A
Uncertainty: 0.002°C
Quality flag convention: no quality flag applied
Method reference: 
Researcher name: Wiley Evans
Researcher institution: Hakai Institute

Salinity 
Abbreviation: Salinity
Unit: 1978 Practical Salinity Scale
Observation type: measurements from continuously flowing seawater stream
In-situ/Manipulation/Response variable: In situ observation 
Measured or calculated: calculated from conductivity and temperature measurements
Sampling instrument: N/A
Analyzing instrument: Sea-Bird SBE 45 MicroTSG Thermosalinograph
Detailed sampling and analyzing information: 1 Hz data captured using National Instruments LabVIEW software on an iMac computer
Replicate information: N/A
Standardization description: N/A
Standardization frequency: N/A
CRM manufacturer: N/A
Poison name: N/A
Poison volume: N/A
Poison correction: N/A
Uncertainty: 0.003 S/m
Quality flag convention: no quality flag applied
Method reference: 
Researcher name: Wiley Evans
Researcher institution: Hakai Institute

Researcher Contact: Please direct questions regarding these data or requests for processing code, 0.5 or 1 Hz processed data, or processing descriptions to Wiley Evans (wiley.evans@hakai.org).