West-Svalbard is distinguished by an elevation in winter temperature¹. Modelling reveal that fast ice coverage, persisting for a duration of two months or more, has undergone a 50% reduction over the past three decades, with the most pronounced diminution observed in western Svalbard. In the inner parts of Billefjorden, a notable reduction in fast ice duration, ranging between three to five months, has been modelled. Overall, western Svalbard has experienced a substantive decline in both sea-ice extent and sea-ice thickness, as delineated in the SESS-report².
Most Svalbard fjords are shaped by glacial activity either by marine terminating glaciers or river deltas, and the bathymetry and size vary between the fjords. Fjords on Svalbard are the most studied habitat, and we divide them into four categories based on the bathymetry and the presence or absence of a shallow sill, or threshold which restricts the inflow of nearby oceanic water masses into the fjord.
Billefjorden is a productive sill fjord with a deep basin, intrusion of water inflow is limited due to the sill creating a barrier. Sill fjord can be as productive as the deep open fjords³ but tend to be dominated by a few Arctic species that are specialists ⁴.
References
¹ Cottier F, Skogseth R, David D, Berge J (2019) Temperature time-series in Svalbard fjords. A contribution from the integrated marine observatory partnership (iMOP). In: Orr et al. (eds): SESS report 2018, Svalbard Integrated Arctic Earth Observing System, Longyearbyen, pp 108-118. https://sios-svalbard.org/SESS_Issue1
²Søreide, J. E., Pitusi, V., Vader, A., Damsgård, B., Nilsen, F., Skogseth, R., ... & Węsławski, J. M. (2020). Environmental status of Svalbard coastal waters: coastscapes and focal ecosystem components.
³(Søreide et al. 2013)
⁴(Søreide et al. 2008)
Written by Sine-Sara Astad, on behalf of the University Centre in Svalbard