University of New South Wales, Australia
Title: Strengthened currents override the effect of warming on
Paulina is interested in the influence of ocean dynamics on ecological processes. Her research involves lagrangian approaches as well as the use of hydrodynamic models in combination with ocean physics theory and empirical data to disentangle physical mechanisms that drive larval transport. Paulina's work establishes mechanistic links between circulation patterns and the dispersal of larvae to envisage implications on population dynamics under different oceanic environmental conditions. She is currently a post-doc fellow at UNSW Sydney Australia exploring past, present and future (under climate change scenarios) larval dispersal patterns along the Eastern Australian Current, a hotspot of ocean warming.
Statement of the Problem: Climate change has induced both strengthening and warming of western boundary currents with widespread implications for the transport and survival of planktonic larvae. However, it has never been explicitly studied how current strengthening and warming affect these larvae, separately. In particular, it is unclear whether the two mechanisms mitigate or enhance each other. Our study estimates changes in larval connectivity and dispersal under an IPCC future climate scenario downscaled to eddyresolving spatial resolution (1/10°), focusing explicitly on the combined and individual impact of ocean warming and current strengthening on larval dispersal. Such understanding is crucial to predict future species distributions, anticipate ecosystem shifts, and design effective management strategies. Methodology & Theoretical Orientation: We simulate contemporary (1990s) and future (2060s) dispersal of lobster larvae using an eddy-resolving ocean model in south-eastern Australia, a region of rapid ocean warming. Findings: We show that warming is favourable for lobster larval settlement along southeastern Australia, but that this is more than offset by the intensification of the East Australian Current, so that the end result is a reduction of 10% in the amount of larvae that reach the coast. In addition, we find a ~270km poleward shift in the settlement peak; these changes in connectivity have the potential to modify the geographical distribution of species in the long-term. Conclusion & Significance: accurate predictions of future larval dispersal patterns cannot be based solely on physiological responses of larvae to temperature. Because climate induced responses off southeastern Australia are weaker than in most western boundary currents, our findings suggest that future redistr bution of species could in fact be stronger in other ocean basins.