Tanika Shalders1,2, Curtis Champion1,2, Kirsten Benkendorff1, Melinda Coleman1,2
1National Marine Science Centre, Southern Cross University, 2NSW Department of Primary Industries
Extreme events such as marine heatwaves have had major impacts on temperate ecosystems and are becoming more intense and frequent. Seaweeds are foundational components of temperate coasts providing nutrition and habitat that underpin a diverse ecosystem. Rich in nutrients such as essential fatty acids, antioxidants, and vitamins, seaweeds support temperate ecosystems from the bottom up. However, it remains poorly understood whether climate-driven environmental change will impact nutrients in seaweeds and their availability to consumers. Using novel lipid- and metabolomics techniques we test the effects of warming and marine heatwaves nutritional quality of two foundational Australian seaweeds; Ecklonia and Sargassum. We then model changes in nutrient availability in response to climate-driven ocean warming throughout each species’ eastern Australian distribution. The consequences of reduced seaweed nutritional quality (e.g. lower levels of essential fatty acids) are likely to reverberate throughout marine food webs, with implications for consumers and the transfer of energy within marine food webs. Understanding how the nutritional quality of primary producers such as seaweeds will be affected by climate change is vital to anticipate and manage climate-driven changes in temperate ecosystems.