Líffræðifélag Íslands - biologia.is
Líffræðiráðstefnan 2025
Erindi/veggspjald / Talk/poster V60
Höfundar / Authors: Sara Harðardóttir(1), Kirstine Drumm(1,2), Kristín J Valsdóttir(1), Steingrímur Jónsson(1), and Nina Lundholm(2)
Starfsvettvangur / Affiliations: 1. Hafrannsóknastofnun, 2. Kaupmannahafnarháskóli
Kynnir / Presenter: Sara Harðardóttir
Shifts in oceanographic conditions have led to significant changes in the composition of phytoplankton communities across the North Atlantic and Polar regions, with a northward expansion of temperate phytoplankton. Iceland is positioned at the intersection of two waterfronts with different ecosystems making it an ideal place to study occurrences and bloom dynamics of HABs in a changing world. The spring bloom is a key event in the Arctic and by long term monitoring of phytoplankton we have collected samples at several coastal and oceanic sites since the 1950s during the spring bloom event. In this study we investigate if there has been an increase in occurrences of the toxigenic diatom genus Pseudo-nitzschia in the North Atlantic water mass correlated to changes in water temperature and salinity. At several study sites Pseudo-nitzschia spp. was enumerated and when possible, compared with eDNA results. We show the occurrences of Pseudo-nitzschia spp. over 15 years in spring at Selvogsbanki and Faxaflói, south and southwest of Iceland, respectively. By retrieving sedimentary ancient DNA from a dated sediment core from the Selvogsbanki area, we investigate occurrences Pseudo-nitzschia decades back in time. The results of this survey will provide a baseline for future assessment of Pseudo-nitzschia in the North Atlantic.