The ocean losing its breath under the heatwaves

Area of Science:

• Oceanography
• Climate Science
• Marine Biology

Background:

• Marine heatwaves, driven by climate change, are increasing globally.
• Seawater oxygen levels are critical for marine life survival.
• The interaction between marine heatwaves and ocean deoxygenation is poorly understood.

Purpose of the Study:

• To assess the global relationship between marine heatwaves and low-oxygen extreme events in the surface ocean.
• To identify regions where these concurrent stressors are intensifying.
• To understand the drivers behind the co-occurrence of these extreme events.

Main Methods:

• Utilized in situ ocean observations.
• Employed state-of-the-art climate model simulations.
• Analyzed data for the surface ocean (0-10m depth).

Main Results:

• Demonstrated a significant surge in the co-occurrence of marine heatwaves and low-oxygen extreme events.
• Identified hotspots where concurrent stressors are more pronounced, particularly in high-biomass regions.
• Attributed the rise in compound events to long-term anthropogenic warming and natural internal variability.

Conclusions:

• Marine heatwaves amplify ocean deoxygenation, leading to more frequent low-oxygen events.
• The ocean's capacity to sustain life is compromised by the increasing frequency of these compound events.
• Findings indicate potentially more severe impacts on marine ecosystems than previously anticipated.