Does thermal stress in adults change the thermal tolerance of offspring? 

The rate of increase of global temperatures is posing significant threat to marine ecosystems, with more extreme weather events such as heatwaves set to be more frequent and intense in the coming years (IPCC 2014).

In 2011, Western Australia experienced record high ocean temperatures peaking at 3°C above mean summer temperatures (Pearce & Feng 2012) resulting in high rates of coral bleaching, intense algal blooms and changes in benthic communities (Rose et al. 2012) with low latitude kelp (Ecklonia radiata) forests found to disappear completely (Wernberg et al. 2018).

Due to the intense and prolonged nature of heat waves in recent years, it is no longer sufficient to predict species responses to future conditions based on ”average warming”.

The response of echinoderms to moderate heat stress is well researched and varies even within regional scales and throughout lifecycles. Typically, short-term physiological responses to warming include an elevation in metabolic and food-consumption rates up to a ‘critical thermal maximum’, followed by a decline in biological functions (Mertens et al. 2015).

When an organism has been exposed to stressful conditions, however, a modulated response can occur to better cope with future warming events. What is unknown is the extent to which this increased tolerance may be passed on to offspring.

Here, we are using simulated marine heatwave events to investigate the impact of extreme and moderate heatwaves on a key benthic herbivore, the sea urchin Heliocidaris erythrogramma, across different life stages and generations, to assess if any thermal stress experienced by adults results in a change in the thermal tolerance of larvae. This will help us gain a better understanding of how this species will respond to thermal stress as heatwaves continue to hit this region.

This study is led by Jay Minuti from the Marine Futures Laboratory, The Swire Institute of Marine Science (SWIMS), at The University of Hong Kong. Jay and her supervisor Associate Professor Bayden Russell are collaborating with newly elected Fellow of the Australian Academy of Science, Professor Maria Byrne from the University of Sydney .