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 .