Research Output Prize 2024-25

What can Earth’s ancient oceans tell us about today’s challenges? For Professor Ryan McKenzie and his collaborators, the answer lies in a dramatic episode of climate change more than 120 million years ago.

Professor McKenzie has received the 2024-25 HKU Research Output Prize for his paper, “A Climate Threshold for Ocean Deoxygenation during the Early Cretaceous,” published in Nature in 2024. The study was led by Dr Kohen W. Bauer, a former postdoctoral fellow in Professor McKenzie’s research group at HKU, alongside an international team of researchers.

The team investigated a period when massive volcanic eruptions released enormous amounts of carbon dioxide (CO₂), driving rapid global warming. By examining chemical evidence preserved in ancient marine sediments, they discovered that once the climate crossed a critical threshold, the oceans lost oxygen rapidly. Even after the initial disruption, oxygen levels took more than a million years to recover, showing how long the consequences of climate change can persist.

Although these events occurred millions of years ago, their significance extends to the present day. As human activities continue to increase atmospheric CO₂ levels, the findings offer valuable insights into how our oceans may respond to global warming.

Professor McKenzie’s research reminds us that understanding Earth’s distant past can help us better anticipate the environmental challenges ahead.

Details of the journal paper:

'A climate threshold for ocean deoxygenation during the Early Cretaceous', Nature, 2024, 633, 582-586, Bauer, Kohen W.*, McKenzie, Ryan*, Cheung, Chris T.L.*, Gambacorta, Gabriele, Bottini, Cinzia, Nordsvan, Adam R.*, Erba, Elisabetta, Crowe, Sean A.*