Líffræðifélag Íslands - biologia.is
Líffræðiráðstefnan 2025
Erindi/veggspjald / Talk/poster V34
Höfundar / Authors: Erin Kathleen Redmond (1, 2), Einar Pétur Jónsson (2), Throstur Thorsteinsson (1), Sara Harðardóttir (2)
Starfsvettvangur / Affiliations: 1. Háskóli Íslands, Environment and Natural Resources, Institute of Earth Sciences, 2. Hafrannsóknastofnun, Environmental Division
Kynnir / Presenter: Erin Kathleen Redmond
Anthropogenic CO₂ emissions are driving ocean warming and acidification, altering phytoplankton growth, distribution, and the potential for harmful algal blooms. This study examined a phytoplankton spring bloom in Krossanes, East Iceland, in 2024, across three depths (0 m, 10 m, 30 m) at two stations (coastal and farther offshore). Species identification and enumeration revealed key bloom-forming taxa and the presence of harmful species at both stations. Chaetoceros convolutus and Corethron pennatum dominated at the coastal station, both capable of damaging fish gills. Pseudo-nitzschia delicatissima, detected at both stations, is generally considered low- or non-toxic; however, some strains can produce the neurotoxin domoic acid. Multi-stressor experiments were conducted on P. delicatissima, simulating ocean conditions projected for 2100. Growth responses such as changes in cell counts and chlorophyll a, were assessed under elevated temperature and pCO₂. Temperature, pH, nutrients, total alkalinity, and domoic acid were monitored during each experiment. P. delicatissima exhibited enhanced growth under warming, slight inhibition under higher pCO₂, and no interaction between stressors. No domoic acid was detected; however, should future strains become toxic and warming promote blooms, ecosystems and human health could be at risk. This highlights the importance of monitoring phytoplankton communities and their responses to climate change.