Estuarine systems are the ecotone between fresh and saltwater environments and are subject to intense natural disturbances. Estuaries are becoming increasingly urbanised and the additional anthropogenic stressors such as contaminants and excess nutrients may be compounded. In response to stressors, resident communities may move, adapt through evolution, or acclimatise via phenotypic plasticity. Therefore, an understanding of an organism’s ability to adjust their eco-physiological homeostasis is required to comprehend how they persist in urbanised estuaries.
Habitat-forming species such as macro-algae are foundational engineers of underwater communities and ecosystems, yet some are declining due to urbanisation. This project uses Ecklonia radiata as a model organism to investigate phenotypic plasticity across an urban gradient in Sydney Harbour, Australia. We collected environmental data (temperature, light, wave exposure, nutrient availability, and contaminants) and measures on kelp morphology, photosynthetic efficiency, and susceptibility to bleaching and biofouling at 8 sites in the Harbour, with varying levels of stressors. We also explored the allelic differentiation of E. radiata to investigate genotype-environment relationships.
As paradigms are shifting in marine conservation, understanding how kelp responds to environmental stressors is essential to predict its fate and anticipate changes in species interactions as well as the eco-evolutionary implications these may have.