Discrete Oxygen Samples on Alfresco for Oregon Shelf BEP

HelpDesk
1

HI!

I have been using Alfresco to download the discrete water sample data sheets from the Cabled Array turn-around cruises to use with the oxygen sensor at the Oregon Shelf BEP. I have noticed a couple of things that may be of interest to others.

  1. Water Summary Spreadsheets are not in the common template that was implemented in 2021
  2. There are no files for Cabled 05 (2014) and Cabled 06 (2015)
  3. There are no CTD casts/discrete water samples for Cabled 07-09 (2016-2018) and Cabled 12 (2021)
  4. CTD data is missing for the discrete samples collected on Cabled 10 (2019) and Cabled 11 (2020)

Are there discrete oxygen samples available for Cabled 05 and Cabled 06? Also, is there a way to request that oxygen samples be collected for Winkler measurements at the Oregon Shelf BEP during the turnaround cruises when the sensors are collecting data for QA/QC of the sensors?

Thank you!

2

Hi Kristen,

Thanks for the note! A few responses:

  1. All summary spreadsheets that we reviewed are in the common template format. Are you looking in the “Water Sampling” subfolder within the cruise data directories? E.g., Cabled Array > Cruise Data > Cabled-12_TN393_2021-07-30 > Ship Data > Water Sampling > Cabled-12_TN393_Discrete_Summary.csv
  2. The discrete sample data from 2014 exists (for the most part), but there were issues with the CTD cast logs and a few other inconsistencies that prevented us from posting the summary .csv file. We will get back to addressing that soon. However, all other Cabled cruises from 06 to 12 have discrete summary sheets. Please double check the directories you are accessing.
  3. Re: the Oregon Shelf BEP, we absolutely take Niskin samples using the ROV prior to recovery and post-deployment in order to get O2 (and other) verification data. Ideally the pre-deployment samples are taken while the instruments are still sampling, but due to the nature of the cabled array (port power needing to be secured prior to unplugging infrastructure, and the testing required before power is turned back on), we can’t guarantee that the samples will be taken while sensors are still collecting data. However, they are collected as close as possible to active sampling times. Unfortunately, we don’t have the resources to collect additional water samples in the area during non-deployment/recovery activities.

If you have examples of directories that are missing summary sheets or any summary sheets that don’t match the common template, please provide links or attach a copy here.

Thanks,
Mike Vardaro & RCA data team

3

Hi Mike,

Thanks for the quick reply! Looks like you and I are looking at the same files. Can you put me in the direction of the discrete oxygen samples collected for Oregon Shelf BEP on the example spreadsheet you referenced for Cabled 12-- I don’t know how I’m missing it. I see the samples collected Axial Base Shallow Profiler, Oregon Offshore Shallow Profiler, etc. but nothing for Oregon Shelf BEP or any other asset shallower than 500 m.

Thanks again!
Kristen

4

No problem!

And you’re not missing it: we did not collect any discrete samples at the BEPs last year (or anything inshore of PN01B) because the primary node was offline between 17 August 2020 and 23 August 2021 due to an overcurrent event that took down the entire southern line of the array. None of the sensors were operating due to the outage, so no verification samples were taken. The system (with the exception of Hydrate Ridge) was repaired in August 2021, and both BEPs are operational so we will be taking water samples this summer.

Sorry for the confusion! We should probably have added a note about that to the Discrete Sample Read-Me file.

-Mike

5

Oh, that makes sense. Are there discrete samples/casts for Cabled 06 - 09 for Oregon Shelf BEP? I can only find discrete samples for Cabled 10 and 11.

Thanks!

6

Unfortunately, what you see in the discrete summary sheets are what we have in our files. No records are unaccounted for. The Shelf site is challenging for ROV operations due to the water depth, and it appears that sampling was intermittent during many of the turnaround cruises. Procedures have become more formalized since 2020, and we will be increasing our sampling going forward.