Following on from Recover issue 4, Dan Crossett and Robyn Dunmore from the Cawthron Institute have had some interesting results from lab experiments set up to test the effects of temperature, turbidity and light on juvenile large brown seaweed growth and survival. We found distinct differences in species’ early life stage responses. Landsburgia quercifolia was more tolerant
of a wider range of conditions, with similar growth and survival across treatments. In contrast, Durvillaea antarctica (rimurapa or bull kelp) was the least tolerant and was strongly affected by increases in temperature and turbidity, with high mortality and slow growth. While Lessonia variegata could survive in the full range of conditions, its growth was significantly constrained with increasing temperatures, and by the lowest light and highest turbidity treatments.

These species-specific responses are important for understanding not only how areas around Kaikōura may recover post-quake, but also how these species may respond to an altered environment under climate change, with higher temperatures, and potentially increased sedimentation and associated lower light levels due to more storm events. In the next step we want to see how different juveniles raised in stressed conditions respond once transplanted into the natural environment, in aspects such as growth and survival.