The long-term impacts of marine heatwaves on biodiversity and management strategies required to mitigate further damage were the focus of a review by researchers at The University of Western Australia.
Professor Thomas Wernberg, Dr Karen Filbee-Dexter and Dr Shinae Montie, from UWA Oceans Institute and School of Biological Sciences, led the review published in Nature Reviews Biodiversity.
"The past two years – 2023 and 2024 – have been the most extreme years on record for marine heatwaves," Professor Wernberg said.
"Globally, marine heatwaves are a natural phenomenon, but they have become stronger, longer and more frequent since 1980 and are being driven by climate change."
The review found species and populations with narrow distributions, limited mobility and proximity to their warm distribution limits were most vulnerable to temperature stress.
Marine heatwaves also had a direct impact on species' productivity and distribution, and indirect impacts through altered species' interactions.
"We found a shift in species' abundance and distribution, decimation of seagrasses, corals and kelps and megafauna mortality," Dr Montie said.
"Impacts on species that play an important part in the ecosystem resulted in cascading changes to the biodiversity, through loss of food sources and habitats."
Rising temperatures resulted in a loss of fisheries, nutrient cycling, carbon storage, ecotourism and cultural values.
"Marine heatwaves have profoundly impacted how humans interact with the oceans," Dr Filbee-Dexter said.
"Marine ecosystem services – the benefits people derive from the oceans – really takes a hit every time the temperatures soar."
The review concluded increasing marine heatwaves were inevitable for the coming decades and reducing greenhouse gas emissions was the only long-term solution to reduce the impact.
"Marine heatwaves have been at the core of environmental, biological, ecological and socioeconomic change in marine ecosystems in virtually all oceans and seas and these impacts have increased exponentially," Professor Wernberg said.
"We need to create flexible fisheries management and swift conservation to protect vulnerable species. Future research should take into account the effects of rising temperature and the compounding stressors."
