A warm stagnant ocean leads to deep-ocean deoxygenation without widespread anoxia

Simulated Ocean Oxygen Under Miocene Boundary Conditions

The Miocene Climatic Optimum (MCO; 16.9–14.7 Ma) was a warm interval with atmospheric comparable to end‐of‐21st‐century projections under intermediate emission scenarios. Proxy records indicate the Oxygen Minimum Zone (OMZ) in the Eastern Tropical Pacific (ETP) was small or non‐existent during the MCO, expanding only...

Observational Evidence for Accelerated Warming and Salinification Propagating Into the Deep Mediterranean

Acceleration, rather than a gradual linear response, is emerging as a defining feature of ocean change in the Anthropocene. Surface‐forced warming propagates into the deep ocean over decades to centuries, but semi‐enclosed basins such as the Mediterranean Sea may respond more rapidly. Here, we analyse an in situ Medite...

A transient global warming event during Earth's penultimate icehouse.

Deep-time hyperthermal/transient warming events provide critical analogs for modern climatic warming and its impacts. However, all ancient hyperthermals documented to date have occurred under greenhouse climate states, limiting their relevance for understanding the trajectory of present-day climate change. Here, we pre...

Reversed marine phosphorus gradient in the Ediacaran Ocean

The Ediacaran Period (635–539 Ma) witnessed the emergence of early animals, rapid oceanic oxygenation, and rising oceanic P availability. However, the relationships among these developments remain intensely debated. Here, we present high-resolution carbonate-associated phosphate (CAP) data from seven Ediacaran sections...

Increased abyssal ocean density stratification across the Middle Pleistocene Transition

Redox-controlled restructuring of marine microbial ecosystems during oceanic anoxic events

During the Phanerozoic, the ocean repeatedly experienced periods of widespread deoxygenation known as oceanic anoxic events. Geological records from these events indicate a profound shift in marine microbial ecosystems. While cyanobacterial biomarkers are found broadly, those of anoxygenic photosynthetic green sulfur b...