For the exact same reason people post links to other things, it's interesting. It's always been more "hacker" than "news" here.

Incidentally, check out this wacky alien-looking worm that exhibits bioluminescence even though it lives its entire life inside of a tube, so there is no one to perceive it: https://en.wikipedia.org/wiki/Chaetopterus

Ocean temperatures have been the subject of a half dozen HN articles (driven by articles in the news) in the past few weeks, so I assume that’s the reason.

Speaking for myself, not Dan, but for non-technical topics that appear on HN, the discussion would be a lot better if the average commentator read the obvious Wikipedia article before commenting. That’s true even though Wikipedia has a lot of problems.

I've submitted them before and often enjoy when they're posted. Sometimes the zeitgeist-link is obvious or sometimes it's a bit random. I'd guess that people who enjoy when they're posted also take to submitting interesting pages they've read (or re-encountered).

They maybe stumbled upon it and found it interesting. There's often no need for context, it can simply be an interesting article to read.

It’s a delightful HN quirk. You can post a direct link to anything you find interesting, apropos of nothing.

Ocean temperatures have been in the news (for me), so I for one can see the context.

Because it is compliant with HN rules.

If you see it in the front page and it bothers you enough to ask the question maybe you should try to find another community.