Has anyone else noticed when in the vacinity of a nirnroot a sort of high pitched ringing occurs. I wonder what this is all in aid of?

It's probably because they're magical or something, so they give out that sound.

So you'll be able to find it if you're not looking right at it. Oblivion had a similar feature.

Nirnroot sound is pretty similar to how it was in oblivion, Nirnroot also acts as a light source at night time, in Oblivion it was used to help find it as there was a small quest line specifically for it. In Skyrim there is no quest for generic Nirnroot but there is for Crimson Nirnroot which also makes the same sound (notably crimson nirnroot is found in blackreach).

I enjoyed the oblivion nirnroot quest, forgot about the noise but now you mention it I do remember. So just to locate them. Carrots and cabbages in barrells also make a sound, oh no, wait, thats me, sighing.

I'm pretty sure there is some kind of lore behind this as well. if you think about the name Nirnroot. Nirn-Root. Nirn is the planet and root is just, what it is. It could as well be called Earth-Root.

It surely was useful for the Crimson Nirnroots, however I am not sure as to why they haven't put the sound just on that one.

Oblivion had the noise too but it was very low. I dont like the noise. Makes it too easy to find them and it gets annoying.

There's a lot of lore behind the Nirnroot.

It's sound drove that Oblivion alchemist , Sinderion I think, to madness.

Yep, they ring and glow at night. Every time I hear it, I'm compelled to stop what I'm doing and get it.

They always grow along water. I found the coast on the other side of the mountain from Solitude has a good number. Also crabs, horkers, and NPC troublemakers. "uh yeah, I'm a guard...that's the ticket"