DOI: 10.21966/1.614670
title: High-resolution record of surface seawater CO2 content from April 2016 to November 2017 collected in Hyacinthe Bay, British Columbia, Canada

description: High-resolution record of surface seawater CO2 content from April 2016 to November 2017 collected in Hyacinthe Bay, British Columbia, Canada.

Quadra Island, at the northern terminus of the Salish Sea, has been a site for shore-based and high-resolution measurement of surface seawater CO2 content since December 2014. Measurements of in situ temperature, salinity, and CO2 partial pressure are made near-continuously from a seawater sample line with an intake 50 m from shore and at a depth of 1 m in Hyacinthe Bay on the eastern side of Quadra Island. The effort to collect these data are part of the Hakai Instituteâ€™s directive to advance the understanding of carbon cycling in northeast Pacific coastal settings with specific emphasis on sea-air CO2 exchange and ocean acidification. This data contribution consists of measurements from April 5, 2016 to November 9, 2017. 

Type of Study: Continuous data record

Temporal Coverage: April 5, 2016 to November 9, 2017

Spatial Coverage: Seawater drawn from 1-m depth approximately 50 m from shore in central Hyacinthe Bay; eastern Quadra Island; northern Salish Sea; 50.1160Â°N, 125.2220Â°W

Platforms: Shore-side laboratory; Hakai Institute Quadra Island Field Station

Version: 1.0

Submission Date: November 12, 2017

Variables:

Partial pressure of carbon dioxide 
Abbreviation: pCO2
Unit: Âµatm

Researcher Contact: Please direct questions regarding these data or requests for processing code, 2-sec processed data, or processing descriptions to Wiley Evans (wiley.evans@hakai.org).

Researcher institution: Hakai Institute
Investigators: Wiley Evans (Hakai Institute), Alex Hare (Hakai Institute), and Katie Pocock (Hakai Institute)

Cite as: Evans, W., A. Hare, and K. Pocock. (2017). High-resolution record of surface seawater CO2 content from April 2016 to November 2017 collected in Hyacinthe Bay, British Columbia, Canada. Version 1.0. Hakai Institute. Dataset. [access date]. 
		
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: bubble-type equilibrator
Analyzing instrument: Dakunalytics, LLC Burke-o-Lator (BoL) pCO2/TCO2 analyzer with LI-COR LI-840A
Detailed sampling and analyzing information: Seawater pCO2 data were calculated from corrected measurements of CO2 mixing ratio (xCO2) made using a Dakunalytics, LLC Burke-o-Lator pCO2/TCO2 analyzer following many recommended protocols by Pierrot et al. (2009) with the system theory and calculations described in detail elsewhere (Hales et al., 2004). Seawater continuously flowed between 0.5 and 1 gpm first through a Sea-Bird SBE45 thermosalinograph and into a bubble-type equilibrator. Seawater supplied to the equilibrator enters the top of the equilibration chamber through a vertical tube before contacting a dispersion plate that diverts seawater radically. Carrier gas (marine air) is pumped into the bubble-type equilibrator from the BoL electronics box at ~200 ml min-1 and enters the equilibration chamber through drip garden hose tubing positioned around the seawater dispersion plate in order to maximize the bubble production and subsequent equilibration of the carrier gas in the chamber. Full equilibration was verified by injecting high and low CO2 gas standard into the equilibration chamber and verifying carrier gas concentrations returned to the same pre-disturbance xCO2. These tests also revealed the response time of the bubble-type equilibrator to be ~5 mins.  Equilibrated carrier gas is then supplied to a non-dispersive infrared gas analyzer (LI-COR LI840A CO2/H2O) housed within the BoL electronics box. Carrier gas is then recirculated through the system, minimizing the need for make-up by the equilibrator. Pressure and temperature were continuously measured in the bubble-type equilibrator using a Honeywell ASCX Microstructure Pressure Sensor and a Omega Fast Response RTD, respectively. Equilibrated carrier gas, four standard gases of known mixing ratio (153.3, 451, 752, and 1515 ppm; Scott-Marin, Inc.), and unaltered marine air were all plumbed to provide gas flow to the BoL electronics box. The BoL is controlled using National Instruments LabVIEW software run on an iMac computer. 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 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 720 minutes, then cycle the actuators to consecutively allow the four standard gas streams and unaltered marine air to be measured for 90 s at 100 ml min-1 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 80 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 1 Hz seawater pCO2, temperature and salinity data were quality controlled, and then bin-averaged in 5-min interval bins. 
Replicate information: N/A
Standardization description: xCO2 calibration functions developed during periodic sequential analysis of gas standards of known concentration (153.3, 451, 752, and 1515 ppm; Scott-Marin, Inc.)
Standardization frequency: Every 720 minutes.
CRM manufacturer: Scott-Marrin, Inc.
Poison name: N/A
Poison volume: N/A
Poison correction: N/A
Uncertainty: 2 ppm for calibrated xCO2; ~2 Âµatm 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. LÃ¼ger, 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; 
Researcher name: Wiley Evans
Researcher institution: Hakai Institute

Sea surface temperature 
Abbreviation: SST
Unit: Â°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: 0.002Â°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: 

Filename: QuadraBoL_5mindata_submission.txt

Column headings: (1) Yearday (2) Year (3) Matlab Time (4) Date and Time (5) pCO2 (uatm) (6)TSG_T (Â°C) (7)TSG_S (PSS-78)