Miss Alissa Bass1,2, Dr Dan Smale2, Dr Kathryn Smith2, Dr Laura Falkenberg1
1The Chinese University Of Hong Kong, , Hong Kong SAR, 2The Marine Biological Association of the United Kingdom, Plymouth, United Kingdom
Coastal marine ecosystems globally are threatened by a multitude of abiotic stressors, such as marine heatwaves (MHWs). MHWs can have differential effects on species, depending on the specific MHW characteristics, and interactions with other environmental factors. Species threatened by extreme warming events include economically and ecologically important foundation species, such as kelps and seagrasses.
Here I present two studies measuring the ecophysiological impact of: 1) MHWs crossed with light limitation on temperate kelps (three Laminaria species) during two seasons, and 2) the impact of MHWs on subtropical seagrasses (two Halophila species). Both experiments showed that species of the same genus have differing responses to simulated MHWs. Within the species’ optimal temperature range, MHWs can elicit favourable growth responses, seen for both kelps and seagrasses. However, these effects can be influenced by seasonality and exposure to additional stressors. For example, when light limitation was induced, MHWs had particularly strong effects on kelp in the summer season, likely because some species are already near their critical thermal maxima, particularly Laminaria digitata.
Our results are encouraging for these important habitat formers as we show that anomalous warming events may not necessarily lead to ecosystem collapse. However, where these MHWs combine with other conditions that drive changes to the dominant macrophyte species in a given habitat, or the biomass of associated flora and fauna, they could have cascading bottom-up effects on marine habitats.
Presentation Slides – Alissa Bass
Biography:
I am a PhD student, studying in Hong Kong. My research focus is examining multiple global change drivers on marine foundation species and the organisms they support, specifically looking at the eco-physiological effects and species interactions. I am particularly interested in studying the impacts of global and regional- scale drivers, such as ocean warming, acidification, and extreme climatic events with more local- scale environmental conditions.
