A nearby supernova causes a superjovian planet of 3000 Terrestrial masses to lose all its hydrogen and helium, over 90% of its mass, transforming it into Ramnu, a glacial globe of 310 Terrestrial masses, later inhabited by small, intelligent gliders.
The italicized passage above is copied from "Unusual Heavenly Bodies," which was originally published on the Poul Anderson Appreciation blog from where it was then copied to the current Poul Anderson Cosmic Environments blog earlier this month.
The idea of the new blog was, first, to make it easier to find earlier-published posts summarizing information about the many extra-terrestrial environments described in Anderson's works of hard sf and, secondly, maybe to add to this information.
One feature of the Ramnuan environment not mentioned before is sulfur:
abundant because of vulcanism;
redistributed by forest fires that are caused by oxygen concentration and lightning;
metabolized by microbes;
vital to several biological functions, including reproduction.
Around an active volcano, the microbes multiply until they are visible as yellow smoke, the Golden Tide. Dying, they enrich the soil but their dwindling brings famine and the sulfur trade has dominated Ramnuan history.
I remembered the phrase "the Golden Tide" from earlier readings but not its meaning until I reread again in search of further details.