If anyone is interested in the overarching project that produced this paper (I assume; authors are PIs on the project), check out TARSAN:

https://thwaitesglacier.org/projects/tarsan

On the AUV front, as well as multibeam from the Hugin, seafloor imagery has been mapped with an AUV named Rán.

I work alongside the team who build Autosub Long Range, who were there in 2022, taking physical/chemical/biological measurements (CTD, microstructure, turbulence):

https://noc.ac.uk/news/boaty-mcboatface-returns-thwaites-gla...

Underwater Gliders have also been deployed under or near the ice sheet to do similar:

https://www.sciencedirect.com/science/article/pii/S096706451...

The "AUV under ice" thing is a fascinating challenge to me. You have to rely a lot on different and novel navigation techniques (like terrain aided/bathymetric navigation and acoustic beacons). And you have to work out how to get your very very expensive robot not stuck under an ice sheet, when its default failsafe is to become positively buoyant, and its primary method of communication (satellite comms) requires a clear view of the sky :-)

The results of the work are.... sobering? Worrying? But I'm glad we're doing them.