Table of Contents

• Coverage
• Dataset Description
  • Methods & Sampling
  • Data Processing Description
• Data Files
• Supplemental Files
• Related Publications
• Parameters
• Instruments
• Deployments
• Project Information
• Funding

Rates of gross oxygen production rates and total daytime oxygen consumption were measured using the ¹⁸O-water in vitro method and membrane inlet mass spectrometry as described by Ferrón et al. (2016).

Seawater samples for the incubations were collected in triplicate before dawn at six different depths (5, 25, 45, 75, 100, and 125m) with 12-L Niskin® bottles attached to a CTD rosette. Subsamples were taken from the Niskin bottles in acid-washed volume- calibrated 150-mLquartz glass bottles with ground-glass stoppers. The bottles were first rinsed with the seawater sample, and then filled from bottom to top using acid- washed silicon tubing, allowing the water to overflow at least twice the volume of the bottles. Before closing, the incubation bottles were spiked with 650 µL of ¹⁸O-H₂O (97.2% ¹⁸O, Medical Isotopes) for the surface samples (5-45 m) and 1,000 µL for deeper samples (75-125 m). The samples were deployed in situ at the corresponding depths before dawn using a free-drifting array, and incubated until dawn. After recovery, the incubated samples were poisoned with saturated mercuric chloride solution to inhibit biological activity. Time-zero samples were also collected pre-dawn and poisoned at the time of the deployment.

Data is processed as described by Ferrón et al. (2016). Gross oxygen production is determined from the change in the 18O isotope ratio of dissolved oxygen over the incubation:

GOP = [R(O2)final - R(O2)initial / R(H2O) - R(O2)initial ] x [O2]initial

where R(O2)initial and R(O2)final are the initial and final isotope ratios (18O/16O) for dissolved oxygen, respectively, [O2]initial is the initial dissolved oxygen concentration, and R(H2O) is the 18O isotope ratio of the incubation water.

The net oxygen change during the incubation is simultaneously determined from the net change in oxygen to argon molar ratios:

NOC = [ ((O2/Ar)final / (O2/Ar)initial) - 1 ] x [O2]initial

where (O2/Ar)final and (O2/Ar)initial are the final and initial oxygen to argon molar ratios, respectively. 

The total daytime oxygen consumption is derived as the difference between GOP and NOC and extrapolated to 24 hours (Ferrón et al., 2016). 

BCO-DMO Processing Notes:
* Adjusted column names to comply with database requirements
* Added ISO8601 format of date and times

NSF Award Abstract:

Intellectual Merit
The PIs request funds to provide training in leading and organizing research cruises to early career researchers in the areas of Biological and Chemical Oceanography. Participants in this training program would be introduced to pre-cruise planning and logistics, receive training in commonly used oceanographic sampling equipment, and conduct shipboard measurements during a 10-day oceanographic cruise to the North Pacific Subtropical Gyre (NPSG). The goal of this training program is to prepare early career scientists for leading and participating in interdisciplinary oceanographic research at sea.

Broader Impacts
The proposed program addresses the broader impacts criteria successfully. The research cruise and follow-up reports and publications focus on interdisciplinary questions important for advancing the field. Given the rapid changes that oceanic systems are undergoing, it is important to have a cadre of junior scientists who are adept at managing interdisciplinary collaborations and conducting research at sea. The PIs are considering ways to connect with diverse audiences in recruiting participants. The impact on early career oceanographers will be very strong. This will create an experience that will be a major impact on the careers of the trainees, especially if they stay in the oceanography field.