Anna Grey @annamgrey.bsky.social · 03/10/2026Hello clever people. Can anyone explain what the white lines are that I see on the Tay? I'm assuming it's something to do with the fact it is tidal and how the Tay interacts with the salt water of the sea? But I'm guessing. 643
Martin Gillie @martingillie.bsky.social · 03/10/2026Sort of thing @jowilliams.bsky.social might know?? 100
Greyrigs @greyrigs.bsky.social · 06/10/2026A complex form of aggregated scum, like others have described, caused by the complex interactions of salt and freshwater, temperature, aeration, currents. 100
Terry O'Connor @osteoconnor.bsky.social · 03/10/2026Could be lines of convergence, dense salt water making a sinking 'front' where it meets fresh? But cleverer people than me may/will/ought to have a better explanation. 100
Mark R @hitchinmark24.bsky.social · 04/10/2026I have always understood these foam lines to be caused by the interaction of different bodies of water, fresh river water and denser saltier sea water in estuaries. The water moves in different directions and causes natural foam along the boundary, like clouds forming on a weather front. 020
ianbonnar3.bsky.social @ianbonnar3.bsky.social · 03/10/2026I'm guessing that it's lines of slip between the fresh water coming down the Tay and the tide. Low Tide was abt 2pm so the speed at which the tide is going out is close to zero at the time of your post. The river is deepest at the Dundee side so that's flowing quicker than the water on the estuary. 110
Taffy Osborne @poppingbubbles.bsky.social · 03/10/2026Probably the interface on a rising tide between the fresh and salt water. It may just be a tidal interface of pure salt water if there is an eddy on either bank, if I was sailing there I would expect the tide to be doing different things on each side of the line. 200
