Tides and transport – opponent for the first time!

Tomorrow, Eli Børve (UiO) is defending her PhD-thesis “Tides and Transport: Application to Lofoten and Vesterålen, Northern Norway” and – for the very first time I’ll be standing “on the other side”, as an opponent. Or standing –  I guess I’ll be sitting, in front of zoom… without flowers, Champagne, proud parents, and everything else that normally comes with a PhD-defense….

Eli has done an impressive job during the last couple of years, working with high-resolution models to study non-linear effects of tidal flow in the many straits of the Lofoten archipelago. I’ve learned a lot while reading her thesis, and I can assure you that it is much more exciting than it may sound! If the tidal current is strong enough, and if the strait opening is abrupt enough – then two vortices may form, one on each side of the strait, that “auto-propagate” (i.e. they move faster than the background tidal current) far enough from the strait opening that they are not caught by the currents when the tide turn. When this process (“tidal pumping”) is at play the transport through the strait, from e.g. the spawning ground of Cod on one side to the open ocean on the other side, is much greater than if the tides were just moving the same water back and forth… pretty cool!

From: Nøst & Børve, Ocean Science 17(5) (2021). Available via license: CC BY 4.0

Much of Eli’s work is already published – and I’m sure she will do just fine tomorrow!

Hopefully, I’ll do too… although I’m admittedly a bit nervous!

(and if you want to learn more about tidal effects on ice shelf melt in Antarctica (guess who came up with the topic!) – then have a look at Eli’s trial lecture here! )