Florian Stahl1, Lea Kappas1, Cátia Monteiro2, Inga Hellige3, Nora Diehl1, Jan-Hendrik Hehemann3, Kai Bischof1
1University of Bremen, Germany - 2CIBIO, Researcher Center in Biodiversity and Genetic Resorces, Portugal - 3Max-Planck-Institute for Marine Microbiology, Germany
Kelp forests are amongst the most divers and productive marine ecosystems providing numerous ecosystem services. Due to climate change and the resulting increase in water temperatures kelp forests are globally declining. We investigated the physiological and biochemical response of Laminaria hyperborea from three different populations along its European distribution gradient to increasing temperatures. Samples were collected in the summer of 2022 in the Porsangerfjorden, Norway and in the summer of 2023 in Heligoland, Germany and Porto, Portugal. After collection and acclimatizion in the laboratory, kelp discs were exposed to water temperatures of 10° C, 16° C, and 22° C for five days. During the experiment, daily measurements of their dark respiration rates and optimum quantum yield of photosynthesis (Fv/Fm) were conducted. After the experimental period, the laminarin content, pigments and C/N ratios were quantified. Preliminary results indicate higher dark respiration rates for samples from Heligoland and Porto, particularly at 22° C. The Fv/Fm values remained relatively stable throughout the experiment with slightly lower values at higher temperatures. Samples from Heligoland and Porto showed higher concentrations of laminarin as samples from Porsangerfjorden. The pigment and C/N ratio analyses are still ongoing and will provide further information on the biochemical changes. These findings will contribute to understanding the resilience of Laminaria hyperborea to rising ocean temperatures and the potential impacts on kelp forests in different climatic regions. Final results will presented and discussed in Brest.
Biography
Florian Stahl is a PhD student at the Marine Botany Lab at the University of Bremen, Germany. His research focuses on kelp ecology, kelp forest afforestation, and the carbon sequestration potential of kelp forests. For his Bachelor’s degree in International Forest Ecosystem Management, he conducted research on mangrove ecology, and for his Master’s degree in Ecology, he focused on coral reef ecology.