OOI CTD and Discrete Water Sampling Data from R/V Atlantis, RVIB Nathaniel B. Palmer AT26-30, AT39-03, NBP1510, NBP1609 in the Argentine Basin from 2015-2018 (OOI Water Sample Data project) (NCEI Accession 0291444)

This dataset contains biological, chemical, optical, and physical data collected on R/V Atlantis and RVIB Nathaniel B. Palmer during cruises AT26-30, AT39-03, NBP1510, and NBP1609 in the South Atlantic Ocean from 2015-03-11 to 2018-01-16. These data include Ammonium, Carbonate concentration [CO3]2-, Nitrate, Nitrite, O2 saturation, Partial pressure of CO2, Silicate, Si(OH)4, silicic acid, beam attenuation, bicarbonate concentration [HCO3]-, bottle salinity, chl_tot, conductivity, depth, depth begin, dissolved Oxygen, dissolved inorganic Carbon, fluorescence, pH, phosphate, salinity, total alkalinity (TA), total phaeopigment, water pressure, and water temperature. The instruments used to collect these data include Apollo SciTech AS-ALK2 total alkalinity titrator, Automatic titrator, Autosal salinometer, Niskin bottle, Sea-Bird SBE 43 Dissolved Oxygen Sensor, and Wet Labs CSTAR Transmissometer. These data were collected by Albert Plueddemann, Ruth Curry, Sébastien Bigorre, and Uwe Send of Woods Hole Oceanographic Institution as part of the "OOI Discrete CTD and Water Sampling Cruise Data (OOI Cruise Data)" project and "Ocean Observatories Initiative (OOI)" program. The Biological and Chemical Oceanography Data Management Office (BCO-DMO) submitted these data to NCEI on 2024-01-02.

The following is the text of the dataset description provided by BCO-DMO:

OOI CTD and Discrete Water Sampling Data

Dataset Description:
OOI-CGSN CTD Sampling Guidelines

In general, water samples are collected for analysis at depths that correspond to instrumentation making in situ measurements. For example, Near Surface Instrument Frames (NSIFs) have instrumentation that measure dissolved oxygen (DO), salinity (CTD), nitrate (NUTNR), the partial pressure of CO 2 (CO 2 ), and chlorophyll a fluorescence, so water samples should be collected at the depth of the NSIF for analyses of all those parameters. Additionally, as noted above, OOI water sampling data are valid long-term datasets in and of themselves. Thus, some measurement locations are driven by broader science questions.

Soak Time – The CTD rosette should be allowed to equilibrate (e.g., the CTD sensor readout stabilizes) at the desired target depth for at least 1 minute or more depending on conditions. Longer soak times may occur to accommodate acoustic release testing or other activities.

Ancillary Sampling – It should also be noted that OOI/CGSN cruises may also include ancillary activities and personnel, such as the Northeast U.S. Shelf Long-Term Ecological Research (NES-LTER) group on Pioneer cruises or the Overturning in the Subpolar North Atlantic Program (OSNAP) on Irminger cruises. These groups may conduct their own CTD casts, and/or collect water samples on OOI/CGSN CTD casts. In some cases, they may collect the OOI/CGSN water samples for analysis. Regardless of who collects the samples, all OOI/CGSN samples (as specified in the sections below) should be noted on the OOI/CGSN sampling logs (3404-00003). Ancillary samples may be noted on OOI/CGSN sampling logs, but should be identified as part of the ancillary program.
Methods and Sampling:
OOI Global Array Sampling Guidelines

Global Arrays are comprised of 2 sub-surface Flanking Moorings, 1 sub-surface Hybrid Profiler Mooring, and at the Irminger Sea Array 1 Surface Mooring. Open Ocean Gliders and Global Profiling Gliders are also present at the Arrays. Subsections below define the strategy for sampling in the vicinity of each type of platform. Given the number of depths required to be sampled at Global Arrays, a 24-bottle CTD rosette is required.

There are a few general guidelines which also inform the strategies defined below:

Nutrient data are useful when validating the Carbon system data. Should get samples spanning the full water depth at one site at least (typically HYPM). Only sample Chlorophyll in the euphotic zone where there is a fluorescence signal detected on the CTD casts. Collect at least one sample per Array where the fluorescence signal is negligible to confirm lack of Chlorophyll.

Sampling at the Global Surface Mooring Location

Sample the full suite (O 2 , Salts, Carbon, Nutrients, Chlorophyll) at the surface, 12, 40, 80, 130 m. Sample Carbon at additional depths where pH sensors are mounted (at 20, 100 m). Also sample O 2 and Salts at intervals below 130 where there are CTD sensors.

Sampling at Global Flanking Mooring Locations

Sample the full suite (O 2 , Salts, Carbon, Nutrients, Chlorophyll) at 30 m. Sample Chlorophyll additionally at surface and the chlorophyll max. Sample Nutrients additionally at 130 m. Also sample O 2 and Salts at 60, 90, 130, 250, 500, 1000, 1500 m

Sampling at the Global Hybrid Profiler Mooring Location

Sample the full suite (O 2 , Salts, Carbon, Nutrients, Chlorophyll) at 30 m. Sample Chlorophyll additionally at surface and the chlorophyll max, and also at 150 m if there is fluorescence signal. Sample O 2 and Salts at 150 m, and ~4-6 places along the profiler path(s)

Sampling at Global Profiling Glider Deployment and Recovery Locations

Sample O 2 , Salts and Nutrients at the surface, 30, 50, 100 and 200 m. Sample Chlorophyll at the surface, 30, 50, 100, and 200 m (if there is a fluorescence signal).

Sampling at Open Ocean Glider Deployment and Recovery Locations

Sample O 2 and Salts at the surface, 30, 50, and every 100 m from 100-1000 m. Sample Chlorophyll at the surface, 30, 50, 100, and 200 m (if there is a fluorescence signal).

Methodology

Salinity

Salinity measurements are performed following the methodology outlined in the WHOI Hydrography Blue Book, Automated Oxygen Titration and Salinity Determination (Knapp et al. 1990). Measurements are performed using a Guildline Autosal model 8400B salinometer (Guildline Instruments of Canada). Manufacturer stated accuracy and precision at 35 psu is +/- 0.003 psu and 0.0002 psu. IAPSO standard seawater is used to standardize the Autosal daily before runs.

Oxygen

Dissolved oxygen measurements are performed following the methodology outlined in the WHOI Hydrography Blue Book _Automated Oxygen Titration and Salinity Determination_ (Knapp et al. 1990). Measurements are performed using a Metrohm Model 888 Titrando dosing device, with the titration endpoint determined amperometrically. Stated accuracy is 0.02 ml/l, with a precision of 0.001 ml/l.

Nutrients

All nutrient values are reported as the average of triplicate analysis on a single collected sample.

Carbon System

Carbon system measurements are performed by the Wang lab (Woods Hole Oceanographic Institution). DIC and TA measurements follow the methodology of Wang and Cai (2004) with uncertainties of 2 umol/kg. DIC measurements are performed with an Apollo Sci-Tech AS-C3. TA measurements are performed with an Apollo Sci-Tech AS-ALK2 and ROSS electrode. pH measurements follow the methodology of Clayton and Byrne (1993) with an uncertainty of 0.002 pH units using an Agilent 8453.

Chlorophyll and Phaeo

Analysis was completed using a Turner Designs Aquafluor Handheld 800446.