Allyson E. Nardelli1*, Wouter Visch1, Glenn Farrington1, J. Craig Sanderson3, Alecia Bellgrove2, Jeff Wright1, Catriona L. Hurd1.
1Institute for Marine and Antarctic Studies (IMAS), 20 Castray Esplanade, Battery Point, 7004, TAS, Australia
2 Deakin University, School of Life and Environmental Sciences, Centre for Integrative Ecology, Warrnambool Campus, Warrnambool, Victoria 3280, Australia
3 Tassal Pty Ltd, 1/5 Franklin Wharf, Hobart TAS 7000, Australia
Resilience to hydrodynamic stress allows kelps to inhabit a range of environments with different intensities of water motion in space and time. Some species have plasticity in their morphology, allowing them to grow in sites with large hydrodynamic forces, whereas other species cannot. Here, we studied the morphological adaptations of Lessonia corrugata (order Laminariales) to different wave exposure levels in Tasmania, Australia. L. corrugata was wild-harvested in the autumn and spring of 2021 at three sites (Coal Point, South Arm and Taroona) with different wave intensities and its morphological characteristics measured (length, number of blades, thickness, width, base angle, number of corrugates and stipe length). We found differences in morphology between the three sites: L. corrugata had characteristics to reduce drag forces on more wave-exposed sites (e.g. increased length and corrugations and reduced number of blades), and the density of L. corrugata individuals within a bed was higher on wave-exposed sites. There was also seasonal variation in morphology. In spring, hydrodynamic characteristics were more apparent due to the higher water motion in that season. Results suggest that L. corrugata is well adapted to sites with a high level of water motion, where the competition for space may be reduced due to hydrodynamic stress.