Current circulation (4)

I believe the answer is:

eddy

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This clue might be a double definition.

'current' is the first definition.
(I know that eddy is a type of current)

'circulation' is the second definition.
The definition and answer can be both related to natural events as well as being singular nouns.
Perhaps there's a link between them I don't understand?

Can you help me to learn more?

(Other definitions for eddy that I've seen before include "Swirl; Duane -, US guitarist" , "religious leader" , "Vortex" , "Chap" , "Ripple" .)

I've seen this clue in the Evening Standard.

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