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Increasing interest in the deployment of optical oxygen sensors, or optodes, on oceanographic moorings reflects the value of dissolved oxygen (DO) measurements in studies of physical and biogeochemical processes. Optodes are well-suited for moored applications but require careful, multi-step calibrations in the field to ensure data accuracy. Without a standardized set of protocols, this can be an obstacle for science teams lacking expertise in optode data processing and calibration. Here, we provide a set of recommendations for the deployment andin situcalibration of data from moored optodes, developed from our experience working with a set of 60 optodes deployed as part of the Gases in the Overturning and Horizontal circulation of the Subpolar North Atlantic Program (GOHSNAP). In particular, we detail the correction of drift in moored optodes, which occurs in two forms: (i) an irreversible, time-dependent drift that occurs during both optode storage and deployment and (ii) a reversible and pressure-and-time-dependent drift that is detectable in some optodes deployed at depths greater than 1,000 m. The latter is virtually unidentified in the literature yet appears to cause a low-bias in measured DO on the order of 1 to 3µmol kg⁻¹per 1,000 m of depth, appearing as an exponential decay over the first days to months of deployment. Comparisons of our calibrated DO time series against serendipitous mid-deployment conductivity-temperature-depth (CTD)-DO profiles, as well as biogeochemical (BGC)-ARGO float profiles, suggest the protocols described here yield an accuracy in optode-DO of ∼1%, or approximately 2.5 to 3µmol kg⁻¹. We intend this paper to serve as both documentation of the current best practices in the deployment of moored optodes as well as a guide for science teams seeking to collect high-quality moored oxygen data, regardless of expertise. 

This dataset contains bottle-calibrated dissolved oxygen (DO) profiles collected from Conductivity Temperature Depth (CTD) casts during cruises in 2020 (AR45) and 2022 (AR69-03) to recover and redeploy Overturning in the Subpolar North Atlantic Program (OSNAP) moorings in the Labrador Sea and western Irminger Sea. DO profiles were used in conjunction with oxygen bottle measurements (Winklers) to produce a post-cruise oxygen-calibrated CTD product for scientific use as part of Gases in the Overturning and Horizontal circulation of the Subpolar North Atlantic Program (GOHSNAP), which has added moored oxygen sensors to the OSNAP mooring array, beginning in 2020. This documentation contains overviews of CTD data collection and processing and of the oxygen sensor calibration method. For each cruise, we provide a summary of relevant cruise events, oxygen sensor calibration results, and issues/problems associated with oxygen data collected. 

This dataset contains discrete sample measurements of dissolved oxygen, dissolved inorganic carbon, and total alkalinity collected during cruises in 2020 (AR45) and 2022 (AR69-03) to recover and redeploy Overturning in the Subpolar North Atlantic Program (OSNAP) moorings in the Labrador Sea and western Irminger Sea. Samples in this dataset were collected as part of Gases in the Overturning and Horizontal circulation of the Subpolar North Atlantic Program (GOHSNAP), which has added moored oxygen sensors to the OSNAP mooring array, beginning in 2020. We provide the discrete sample measurements alongside salinity- and oxygen- calibrated Conductivity Temperature Depth (CTD) and oxygen sensor data from the depths where Niskin bottles were closed for sample collection. 

This dataset contains bottle-calibrated dissolved oxygen (DO) profiles collected from Conductivity Temperature Depth (CTD) casts on turn-around cruises performed yearly to maintain the Ocean Observations Initiative (OOI) Global Irminger Sea Array (60.46°N, 38.44°W). DO profiles were used in conjunction with oxygen bottle measurements (Winklers) to produce a post-cruise oxygen-calibrated CTD product for scientific use. Bottle-calibrated CTD salinity products were used to produce post-cruise oxygen-calibrated CTD profiles starting in 2018 (Year 5). This document contains overviews of CTD data collection and processing and post-processing oxygen sensor calibration method. Reports for each cruise include a summary of relevant cruise events, oxygen sensor calibration results, and issues/problems associated with oxygen data collected on each cruise. This dataset has been created for end-users that require field-calibrated oxygen data products that are currently not provided by OOI through its standard data dissemination. 

This dataset contains discrete sample measurements of dissolved oxygen, dissolved inorganic carbon, and total alkalinity collected during yearly Ocean Observatories Initiative (OOI) turn-around cruises to maintain the Irminger Sea Array (60.46°N, 38.44°W). Samples in this dataset were collected as part of an ancillary research project that joined the OOI turn-around cruises in June 2018 and August 2019 as part of ongoing efforts to enable OOI biogeochemical sensor data to be used to address scientific questions about ocean carbon cycling and the biological carbon pump. Discrete sample data collected and analyzed by this research team complement data collected by the OOI program as part of routine turn-around cruise activities. We provide the supplementary measurements made by our team alongside salinity- and oxygen- calibrated Conductivity Temperature Depth (CTD) and oxygen sensor data from the depths where Niskin bottles were closed for sample collection and additional discrete oxygen measurements made by the OOI team. 

The field of oceanography is transitioning from data-poor to data-rich, thanks in part to increased deployment ofin-situplatforms and sensors, such as those that instrument the US-funded Ocean Observatories Initiative (OOI). However, generating science-ready data products from these sensors, particularly those making biogeochemical measurements, often requires extensive end-user calibration and validation procedures, which can present a significant barrier. Openly available community-developed and -vetted Best Practices contribute to overcoming such barriers, but collaboratively developing user-friendly Best Practices can be challenging. Here we describe the process undertaken by the NSF-funded OOI Biogeochemical Sensor Data Working Group to develop Best Practices for creating science-ready biogeochemical data products from OOI data, culminating in the publication of the GOOS-endorsed OOI Biogeochemical Sensor Data Best Practices and User Guide. For Best Practices related to ocean observatories, engaging observatory staff is crucial, but having a “user-defined” process ensures the final product addresses user needs. Our process prioritized bringing together a diverse team and creating an inclusive environment where all participants could effectively contribute. Incorporating the perspectives of a wide range of experts and prospective end users through an iterative review process that included “Beta Testers’’ enabled us to produce a final product that combines technical information with a user-friendly structure that illustrates data analysis pipelines via flowcharts and worked examples accompanied by pseudo-code. Our process and its impact on improving the accessibility and utility of the end product provides a roadmap for other groups undertaking similar community-driven activities to develop and disseminate new Ocean Best Practices.