Abstract:
Local and global environmental change has led to the continued decline of coral reef ecosystems worldwide. Unfortunately, coral reefs of the Red Sea are following the same trajectory and showing signs of degradation in response to warming and marine heat waves. Through the research in my group, we are exploring what rapid environmental change, in the already hot and salty Red Sea, means for the future of coral reef communities. I will share some of the first results from the Global Change Ecology lab, touching on our three current pillars of research: biodiversity of coral reef algae, response of reef algae and communities to warming, and impacts of environmental change on reef ecosystem structure and function. Through surveys conducted along the length of the Red Sea we’re finding an incredible amount of previously undescribed biodiversity in key calcified algal taxa, including never-before described species. These species are an essential component of Red Sea reefs, where they can cover upwards of 50% of the benthos, yet we still know little about their ecological functions and how they’re affected by environmental change. Our work is shedding light on their identity, function, and sensitivity to thermal stress. Despite the high thermal tolerances of Red Sea reefs, the recent marine heat wave events of 2023 and 2024 are having detrimental effects on these taxa and reef communities, more broadly. Emerging evidence from our field and laboratory studies indicates that, although some species are more thermally tolerant, the extreme temperatures of the last two years have surpassed the thresholds of tolerance for many taxa. These results have important implications for the future of coral reefs in the Red Sea, and shed light on the winners and losers in the rapidly warming ocean.

Bio:
Maggie Johnson is an Assistant Professor of Marine Science at King Abdullah University of Science and Technology (KAUST) where she is leading the Global Change Ecology Lab. She has devoted her career to tackling the question, how are humans altering the face of coral reefs and what does this mean for the future of coral reefs? Professor Johnson studies coral reefs across the globe, from the central tropical Pacific to Caribbean Panama and the Red Sea, and seeks to understand what role humans are playing in the rapid degradation of these valuable ecosystems. She uses a combination of field and laboratory-based approaches to 1) evaluate and monitor the structure and function of coral reef ecosystems, 2) quantify inherent natural heterogeneity in key environmental parameters including temperature, dissolved oxygen, and pH, 3) explore the implications of environmental change for ecophysiology of coral reef primary producers, 4) and determine the implications of local and global environmental change for these foundational coral reef taxa. By focusing on lesser studied taxa on coral reefs, the calcifying algae, she and her team are providing some of the first insights to how changes in the Red Sea environment will shape reef communities in the coming years. In addition to her research interests, Prof. Johnson is strongly committed to supporting women and underrepresented groups in the sciences and actively works on recruiting and supporting a diverse research group.