Norwegian version of this page

Disputation: Eli Børve

Doctoral candidate Eli Børve at the Department of Geosciences, Faculty of Mathematics and Natural Sciences, is defending the thesis Tides and Transport: Application to Lofoten and Vesterålen, Northern Norway for the degree of Philosophiae Doctor.

Eli Børve. Photo: Yngve Vogt/Apollon

Eli Børve. Photo: Yngve Vogt/Apollon

The PhD defence and trial lecture are fully digital and streamed using Zoom. The host of the session will moderate the technicalities while the chair of the defence will moderate the disputation.

Trial lecture

The importance of tides for ice shelf melt in Antarctica

Conferral summary (in Norwegian)

I mange norske kystområder er tidevannet en viktig pådriver for bevegelser i vannet. Selv om tidevannet i all hovedsak beveger vannet frem og tilbake (som i sum er like langt) kan tidevannet i møte med kysten eller havbunnens topografi også generere mer ensrettede tidsmidlede strømmer og flukser, og på den måten være en viktig komponent for transport av partikler, som for eksempel fiskeegg og -larver, næringsstoffer, samt søppel og forurensing. Avhandlingen viser viktigheten av de tidevannsgenererte «transportårene» i havområdet rundt Lofoten og Vesterålen, som har viktige gyteområder for den nordøstarktiske torsken eller skrei på folkemunne.

Main research findings

Popular scientific article about Børve’s dissertation:

Tides and Transport: Application to Lofoten and Vesterålen, Northern Norway

Tides are important drivers for the motion in many coastal seas. While tides mainly move water back and forth, the interaction between tidal currents and topography might induce residual currents and fluxes, providing an important transport component. The coastal sea around Lofoten and Vesterålen is an area where strong tidal currents interact with complex coastlines and topography. However, the tidally-induced transport has gained little attention.

Image may contain: Ecoregion, Map, World, Slope, Rectangle.
Figure: Transport pathways towards the Norwegian shelf region for "cod eggs" released at the spawning-ground Henningsværstraumen in Vestfjorden. The left panel show the transport pathways when tides are present, while the right panel shows the transport pathways when tides are absent. When tides are present, about 60% of the particles exit Vestfjorden south of Røst, while about 30% of the particles take the short-cut through Moskstraumen. Without tides almost 90 % of the particles exit Vestfjorden south of Røst, while only a small fraction exits through any of the straits. Credit: Eli Børve

The coastal sea around Lofoten and Vesterålen is the main spawning ground for the Northeast Arctic cod, the most important species in Norwegian fisheries. The recruitment of this fish stock depends on ocean currents transporting eggs and larvae to its nursing ground in the Barents Sea. Thus, to identify vulnerable areas and predict fish recruitment for sustainable fisheries management, understanding the processes determining transport pathways is vital.

This thesis shows the importance of tidally-induced transport in Lofoten and Vesterålen. The thesis comprises theoretical and model studies investigating different transport processes and a comparison study on particle transport with and without tides. The results show that tides largely impact the particle transport in the region, both by increasing the transport from a spawning-ground in Vestfjorden to the shelf and by influencing which routes the particles take.

Photo and other information:

Press photo: Eli Børve, portrait; 1000px. Photo: Yngve Vogt/Apollon

Other photo material: Figure with description and credit as specified in the article above, size 1600px.

Published Dec. 2, 2021 11:57 AM - Last modified Dec. 26, 2021 2:45 PM