# Southern_Ocean-06_DY111
---
Author: Andrew Reed
Date: 2024-04-11
Version: 1-00
---
### File Processing
##### Methodology
There should be one row for each station-cast-niskin bottle. Multiple samples for the same
parameter from a single niskin bottle are split into separate rows, with the associated
CTD data copied to the new row. The first row of the file is the column headers.
Two different CTDs were used on cruise DY111: a stainless steel and a titanium CTD. The
casts performed with the titanium are identified with a "t". Additionally, the calibrations
for all of the stainless steel CTD sensors were over 1-year old. On the titanium CTD, the calibrations
for the secondary conductivity, fluorometer, and transmissometer were over 1-year old.
This cruise was performed in conjuction with the British National Oceangraphic Center as
part of their CUSTARD project. As detailed in OOI's Southern Ocean 6 Cruise Report (Control Number: 3201-00603),
no CTD casts were conducted during the Southern Ocean 6 Cruise DY112, but the CUSTARD
team conducted CTDs in the vicinity of the GS01SUMO-00004 mooring during the previous
CUSTARD cruise DY111. All water sampling was performed by them. Much of the data
is also available via the British Oceanographic Data Center (BODC), thus this Discrete Summary
contains data supplied by Natural Environment Research Council.
##### Notes
| Station-Cast # | Bottle Position | Comment |
| --------------- | --------------- | ------- |
| 2 | All | Caps not removed from transmissometer. |
| 3 | All | Matched Niskin/Bottle Position to Cast Log Sheet, which indicated odd-numbered Niskins were sampled. |
| 3t | All | Bottle data could not be retrieved and processed. |
| 4t | 18, 19, 20 | Comparing the salinities between the two conductivity sensors showed a measured difference >0.1 psu |
| 5t | 11, 20, 24 | Comparing the salinities between the two conductivity sensors showed a measured difference >0.1 psu |
| 7t | 21 | Comparing the salinities between the two conductivity sensors showed a measured difference >0.1 psu |
| 15t | All | This cast had modulo errors. |
| 15t | 1-12, 14-15, 17-19, 22-23 | Comparing the salinities between the two conductivity sensors showed a measured difference >0.1 psu |
| 18t | All | The xmlcon file for this cast is corrupt. Bottle data could not be retrieved and processed. |
### Salinity
##### Methodology
Salinity measurements were performed using a Guideline Autosal 8400B (s/n 68426).
A standard was run as a sample before and after each crate of samples as a control.
The Autosal was standardised using IAPSO Standard Seawater batch P162 (K15=0.99983, 2xK15=1.99966, 34.993 PSU).
##### Notes
Discrete Salinity values were flagged when there was a greater than +/- 0.1 difference to corresponding CTD Salinity. Corresponding CTD Conductivity 1 and 2 also flagged.
From stainless steel CTD: Nothing to note.
From titanium CTD: Samples drawn but analysis not yet received.
### Oxygen
##### Methodology
Seawater samples for dissolved oxygen concentration were directly collected from the Niskin
bottles in the clean laboratory to avoid their contamination. Seawater was siphoned into 100 ml
borosilicate glass bottles (nominal volume, actual volume was determined gravimetrically prior
to the cruise), using silicone tubing and overflowing 2 times the bottle volume, and samples were
immediately fixed. Oxygen in the samples was fixed with Manganese Sulphate and Alkaline Iodide
solutions dispensed from calibrated pipettes. The fixing temperature was recorded on a hand-held
thermometer. Immediately after fixing, the samples were stored until analysis. Titrations for
dissolved oxygen determination were made within the following 12 h. The concentration of
thiosulphate was calibrated prior to starting oxygen analyses as well as blank determination.
Oxygen saturation was calculated from the equations for solubility in seawater of Benson and Krause (1984).
Dissolved Oxygen (DO) was determined by automated Winkler titration with potentiometric end-point
(Williams and Jenkinson 1982) using a Metrohm 916 Ti-Touch controller and 2 Metrohm Dosino 800 units
for dispensing Thiosulphate and Iodate solutions. A Metrohm Pt-Titrode electrode was used for detecting
the potentiometric end-point of the titration. The titration sequence and data acquisition were controlled
by Metrohm Tiamo software.
We used factor 44.661 to convert umol/L to mL/L.
Benson, BB and Krause DJr. (1984) Limnol. Oceanogr., 29, 630-632.
Williams, PJleB and Jenkinson NW (1982) Limnol. Oceanogr. 27, 576-584.
##### Notes
| Station-Cast # | Bottle Position | Comment |
| --------------- | --------------- | ------- |
| 38 | 5 | Flagged in data provided by CUSTARD team |
### Nutrients
##### Methodology
All nutrient values are reported as the average of triplicate analysis on a
single collected sample. The data were run and processed by Edward Mawii of
the NOC.
For data provided as Nitrate + Nitrite, we subtracted the provided Nitrite
to populate our column for Discrete Nitrate.
##### Notes
From stainless steel CTD: Nothing to note.
From titanium CTD: Samples drawn but analysis not yet received.
### Carbon System
##### Methodology
##### Notes
Sample analysis is still underway.
### Chlorophyll and Phaeo
##### Methodology
Fluorometric analysis of chlorophyll a.
Moore et al., 2007; doi:10.1016/j.dsr2.2007.06.015
##### Notes
Nothing to note.
---
### Data Flag Description
The data flags are presented in the summary sheet as a 16-bit array, read from
right-to-left, where a 1 in a particular bit position indicates a particular
flag meaning applies. For example, a flag of 0000000000000010 for the column
**CTD File Flag** indicates that the cast was a data cast only.
Additionally, these data flags an assessment of the collection and processing
of the relevant data or samples, and are not an assessment of the *accuracy*
of the data. For example, a conductivity sensor which has the correct
calibration coefficients and functions normally will receive a quality flag of
0000000000000100 (acceptable measurement). However, the calibration
coefficients may be out of date and off with respect to the discrete salinity
results; this does not affect the assigned flag.
| Bit Position | Cast Flag | CTD File Flag | CTD Parameter Flag | Niskin Flag | Discrete Sample Flag | Discrete Replicate Flag |
| ------------ | ------------------------------------------------------ | ------------------------------------------------- | ------------------------------------------------ | -------------------------------- | ------------------------------------------------------------------- | ------------------------------------ |
| 0 | Notes/Other | Notes/Other | Notes/Other | Notes/Other | Notes/Other | Notes/Other |
| 1 | Delayed start to data collection | Data cast only | Not Calibrated | Bottle information unavailable | Sample for this measurement was drawn but analysis not yet received | Duplicate analysis on same Sample |
| 2 | Acceptable; normal cast according to SOP | Acceptable; file processed according to SOP | Acceptable measurement | No problems noted | Acceptable; sample processed according to SOP | Single Sample |
| 3 | Non-standard winch speed | File processed using modified parameters | Questionable measurement | Leaking | Questionable measurement | Duplicate analysis from same Niskin |
| 4 | Non-standard surface soak time | File processed using alternate XMLCON | Bad measurement | Ran out of water during sampling | Bad measurement | Triplicate analysis from same Niskin |
| 5 | Non-standard bottle soak time | Missing scans as indicated by module error counts | Not reported | Vent open | Not reported | Unassigned |
| 6 | Sensor issues but cast completed and data collected | Missing metadata | Calibration coefficients greater than 1 year old | Misfire at wrong depth | Sample collected out-of-order | Unassigned |
| 7 | Cable issues but cast completed and data collected | Unassigned | Corresponding discrete sample | Unknown problem | Sample processed using alternative methods; see notes | Averaged value from replicate samples|
| 8 | Winch issues but cast completed and data collected | Unassigned | Unassigned | Unassigned | Unassigned | Unassigned |
| 9 | Premature cast end with data and/or data loss | Unassigned | Unassigned | Unassigned | Sample not drawn for this measurement from this bottle | Unassigned |
| 10 | Significant ship heave | Unassigned | Unassigned | Unassigned | Unassigned | Unassigned |
| 11 | Station position not adequately maintained during cast | Unassigned | Unassigned | Unassigned | Unassigned | Unassigned |
| 12 | Tow-yo, Yo-yo cast | Unassigned | Unassigned | Unassigned | Unassigned | Unassigned |
| 13 | ROV Bottle sample | Unassigned | Unassigned | Unassigned | Unassigned | Unassigned |
| 14 | Unassigned | Unassigned | Unassigned | Unassigned | Unassigned | Unassigned |
| 15 | Unassigned | Unassigned | Unassigned | Unassigned | Unassigned | Unassigned |