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| Oxygen-deficient zones (in red) shrank during long warm periods in the past, contrary to widespread expectations. Image Credit: Alexandra Auderset, Princeton and MPIC |
In the last 50 years, oxygen-deficient zones in the open ocean have increased. Scientists have attributed this development to rising global temperatures: Less oxygen dissolves in warmer water, and the tropical ocean’s layers can become more stratified.
But now, contrary to widespread expectations, an international team of scientists led by researchers from the Max Planck Institute for Chemistry and Princeton University has discovered that oxygen-deficient zones shrank during long warm periods in the past.
“We had not expected such a clear effect,” said Alexandra Auderset, first author of the new paper in the journal Nature and currently a visiting postdoctoral research fellow at Princeton University. She led the study with Alfredo Martínez-García at the Max Planck Institute for Chemistry in Mainz, as part of a long-term collaboration with Daniel Sigman’s group at Princeton University.
Understanding these changes is important because “when oxygen becomes scarce, life has a harder time,” said Sigman, Dusenbury Professor of Geological and Geophysical Sciences. For example, in low-oxygen regions of the eastern Pacific and northern Indian Ocean, only specialized microbes and organisms with a slow metabolism — such as jellyfish — can survive.













