There’s also this (much longer, but very helpful) science brief: oceanrep.geomar.de/id/eprint/59... which includes a nice graphic on it:

Which brings us back to our lovely schematic. Our results highlight that ventilation occurs all along the subpolar gyre pathway, in contrast to previous studies (including my own) that focused largely on the Labrador Sea for O2 uptake/ventilation

So does this mean the Lab Sea doesn’t matter?

11/🧵

To understand why, we turned to an Argo float that tracked the circulation through the SPNA.
The data shows that water is progressively modified: light water becomes SPMW, which becomes denser SPMW, which becomes LSW. The high O2 of LSW is the end result of uptake throughout this process

10/🧵

Going back to the observational data, O2 levels increase during winter in different water masses - ocean layers defined by their density - as a result of the uptake.

Surprisingly, the change is strongest in subpolar mode water (SPMW), not Labrador Sea Water (LSW), the highest O2 water mass

9/🧵

Analyzing data from an ocean model we find similar patterns, and also see that the positive oxygen uptake is balanced by a negative transport divergence - implying that the oxygen absorbed from the atmosphere is subsequently carried away by ocean currents.

8/🧵

This allowed us to estimate the air-sea exchange of oxygen for the whole SPNA; previous studies had only been able to sample at a single location.

We find that almost the entire SPNA (green box) is an annual oxygen sink, meaning O2 flows from the atmosphere into the ocean year after year

7/🧵

Which is where our study comes in - improving our understanding of how the North Atlantic is ventilated currently

To find out, we used GOBAI-O2, a data product created by @jdsharp.bsky.social with the help of an army of ocean robots that sample all over the world (@bgc-argo.bsky.social)

6/🧵

Why do we care about oxygen in the ocean? Well, because things living there need to breathe

And unlike those of us breathing air, ocean organisms can’t always rely on there being enough O2. Without sunlight for plants to grow below ~200m, ventilation is the main O2 supply for most of the ocean

3/🧵

Our new 🌊 paper “Progressive oxygenation of the North Atlantic Subpolar Gyre” is out @jgroceans.bsky.social (open access): agupubs.onlinelibrary.wiley.com/doi/10.1029/...

We examined the breathing of one of the ocean’s lungs 🩺 and found some surprises

Paper summary in schematic, more info ⬇️

1/🧵

Hobbes would like to remind everyone that it’s important to take breaks from work

First installment of #OSM24 soccer 🌊⚽️