Oxygen_SOP/sections/oxygen_pre_deployment

[utterances-bot]

3. Pre-deployment operations and calibrations — Oxygen SOP

https://oceangliderscommunity.github.io/Oxygen_SOP/sections/oxygen_pre_deployment.html

[ptestor]

• [x] Need to reformulate "After recovery the sensor and to remove any biofouling, the following protocol is recommended by the manufacturer:" (Soeren: dealt with in #111)

• [ ] section 3.3.2: How do we manage the photo metadata? I think it is a good idea. We could include a post-recovery biofouling metadata scored from 1 to 5 for example if we provide examples. But then how would this value be used? We should develop on this. (Soeren: dealt with in #113)

• [x] section 3.4.1: reformulate: "within the core of the Peruvian oxygen minimum zones oxygen concentrations at nmol levels are present other approaches for 0 % in-situ calibration" (Soeren: dealt with in #111)

• [ ] I have the feeling that we would need to add a few sentences to explain why all this must be done. It is probably done in DMQC section but a few words here would definitely not hurt. (Soeren: dealt with in #117 and #161)

[s-pearce]

In section 3.4.1.2 # 3 it says to "Do Stop" is the command to stop the Aanderaa 4831/4330 from sampling and to use "CR + LF" in the terminal. This is a bit of a mixed message. In optode firmware versions smaller than 3.x.x (Framework 3), it did not require the "CR + LF", only the "CR" and the command to stop was "Do Stop". In 3.x.x and higher (as of 2021, in 5.x.x framework), the optode does require "CR+LF" and the command to stop was changed to only a "Stop", no longer requiring the "Do". This is described in Appendix 11 "Product Change Notification: Framework 3" in the Aanderaa 4330/4835/4831 Optode manual. Anyway, nobody is likely to use firmware less than 3.x.x anymore, so I suggest that the "Do Stop" change to "Stop" above.

• [x] (Soeren: transferred into #144)

Also, I believe it was framework 3 that first allowed the SVU/Multipoint-calibration, and firmware less than 3.x.x only used the Mk2 equation. -Stuart Pearce

• [x] (Soeren: transferred into #145)

[isgiddy]

In section 4.5.1, on doing the experiments at two different temperatures I have a few points that I would like clarification.

• [x] 1. If the temperature range of planned measurements is small, (5 degrees celcius), is it still recommended to run at two temperatures? #157

• [ ] 2. For very low expected temperatures (-1.5-2), do we need to run this in a freezer room, or would it be acceptable to calibrate at higher temperatures? The SOP only recommend using as AC to change the temperature for example. #158

• [x] 3. For each temperature run should we leave all materials, reagents and sensors in the lab/workshop/room overnight? #159

[nbronikowski]

Hi everyone, what is the recommended sample interval for optodes? Factory setting on our optodes is 5 seconds (AADI 4831). What do other users use?

[soerenthomsen]

Hi @nbronikowski,

in section 5.6.1. Gather data to help correct for sensor response time we write: "Several parameters, namely response time, profiling velocity and vertical oxygen gradient, have an impact on a feasible sampling interval and therefore on the error of the reconstructed true oxygen profile (Bittig et al., 2014). (Bittig et al., 2014) mentions that “the sample interval should be significantly shorter than the response time τ to resolve gradient regions and to be able to reconstruct the true oxygen profile.” Thus, a sufficient high frequency sampling, here interpreted as an order of magnitude faster, is required for a good lag correction. In particular in areas with a strong oxycline, we recommend to always sample at 5 s period. If battery lifetime is an issue, periodic up- and down dives with high frequency sampling are more useful than continuous measurement at a lower frequency."

Hope this helps!

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