Dr Sarah Lau1, Dr T.Y. Hui1, Prof. Gray A. Williams1
1The Swire Institute of Marine Science and the Area of Ecology & Biodiversity, School of Biological Sciences, The University of Hong Kong, Hong Kong SAR, ,
The ability to withstand sublethal thermal stress (such as increased energy demand) is increasingly recognized as a key criterion to determine species survival and distribution in the warming future. Metabolic depression, for example, is one effective strategy that conserves energy and resources to cope with prolonged adverse conditions. This strategy may be particularly crucial to survive on tropical high shores, where organisms are not only frequently exposed to extreme temperatures but also energy constrained. To investigate how such metabolic adjustments may benefit survival in thermally harsh conditions, cardiac thermal performances of the tropical high shore littorinid, Echinolittorina malaccana, were examined from six populations across the species’ geographic distribution. Snails were assessed either immediately (field fresh) or after acclimating to hot or cool regimes in common garden experiments to assess whether and to what extent metabolic depression varied across populations experiencing different climatic conditions. Variation in thermal tolerance of field fresh snails coincided with the thermal but not the latitudinal gradient of the populations, indicating that local conditions (e.g. tidal cycle and wave exposure) overrode latitudinal, climatic effects in driving the thermal responses of these snails. Upon acclimation, the cardiac thermal performance of snails from all populations converged to a similar pattern where hot-acclimated snails showed an overall more depressed metabolism and slightly enhanced thermal tolerance as compared to cool-acclimated snails. Such convergence highlights phenotypic plasticity in the metabolic depression trait and suggests that recent thermal history could be key to invoke energy balance strategies in thermally dynamic and extreme habitats.
Biography:
Sarah is working with a group that is quite special in the ITRS family – this group is based in Hong Kong and technically works on ‘tropical’ reefs instead of ‘temperate’ reefs – so hopefully she will bring insights from a different angle!
