Nora Salland1,2, Catherine Wilding1,3, Cristina Galobart4, Kathryn Smith1, Nathan King1, Michael Burrows5, Dan Smale1
1Marine Biological Association, UK - 2University of Southampton, UK - 3University of Newcastle, UK - 4Centre for Advanced Studies of Blanes, Spain - 5Scottish Association for Marine Science, UK
Climate change profoundly impacts habitat-forming species in marine ecosystems, such as kelps (large brown seaweeds) which are found along temperate rocky reefs. These changes drive shifts in ecosystem composition, functioning, species diversity, and the provisioning of ecosystem services. Ocean warming, in particular, is causing a global redistribution of species. Biogeographic transition zones serve as hotspots for range shifts, where warm- and cold-adapted species meet at opposing range edges. Our research examines temporal changes in kelp forest composition and abundance across seven kelp species by comparing historical field observations (from 1941–2012) with contemporary survey data (2021–2023) collected from 34 sites in SW England, a biogeographic transition zone in the Northeast Atlantic. We recorded shifts in kelp composition, finding an increase in warm-temperate Lusitanian kelps (i.e., Saccorhiza polyschides and Laminaria ochroleuca) alongside a decline in some cold-temperate Boreal kelps (such as Saccharina latissima and Alaria esculenta). Our findings also indicate a rise in sea surface temperature over time, corresponding to an increase in the community temperature index (CTI) of kelp forests. This reflects a shift toward warm-temperate kelps becoming dominant in these habitats. Experimental studies further explored the physiological tolerances of kelp species and populations along a latitudinal gradient, providing insights into their adaptive potential under changing climates. The ongoing trend of ocean warming is anticipated to drive further shifts in the distribution and abundance of canopy-forming kelps, with consequent changes to broader kelp forest composition. As ecological functions and traits differ between kelp species - particularly between warming ‘winners’ and ‘losers’ - these changes may have significant implications for ecosystem service provision and ecological resilience.
Biography
Nora finished her fieldwork-heavy PhD project and submitted her dissertation entitled “Examining climate-driven shifts in the ecological structure and functioning of Northeast Atlantic kelp forests” last year. Nora’s current postdoc focuses on the interaction of kelps and their microbial communities in the North Pacific. For her future career, she likes to focus again on broader kelp forest ecology, ecosystem structure and functioning, and ecosystem services provided by kelp forests.