It doesn't sound like the coast guard icebreakers server a purpose, so this is really a decline to zero.
They did research when I served, a mere 50 years ago! These days, as part of DHS, not DOT, I can imagine that research is a dirty word compared to "projecting national interests" and the Commandant was summarily dismissed for predictable reasons. So I can't say what research, if any, is conducted these days. One can ask.
A recent comparison of CG and NSF breakers, the latter of which is now zero, is in this congressional report. Physical page 45.
https://www.congress.gov/crs_external_products/RL/PDF/RL3439...
Strong parallel to rockets and high-altitude planes used for atmospheric research ...
Here is the place to look for research. I did look up the R&D center a while back with my impending 50 year anniversary of service. I was in the Physics branch and knew buddies in oceano.
Our guy Dennis got multispectral photos of ice with a Hasselblad UV-Sonnar. Quartz and CaF elements. Who can forget that?
https://www.dcms.uscg.mil/Our-Organization/Assistant-Command...
HTH