HomeScienceAncient Extinction Mirrors Today’s...

Ancient Extinction Mirrors Today’s Ocean Crisis: Deoxygenation’s Role Unveiled

Deoxygenation and Marine Extinctions

A study in Nature Geosciences reveals that oceanic anoxia significantly contributed to marine extinctions during the Triassic–Jurassic period, with current levels of deoxygenation mirroring those of the past. This discovery highlights the sensitivity of marine ecosystems to local and global environmental changes.

Scientists have discovered a pivotal role of oceanic anoxia in the TriassicJurassic mass extinction, indicating that even localized deoxygenation can lead to widespread ecosystem collapse. This research emphasizes the importance of understanding current marine ecosystem fragility in the face of increasing deoxygenation.

Scientists have made a surprising discovery that sheds new light on the role that oceanic deoxygenation (anoxia) played in one of the most devastating extinction events in Earth’s history. Their finding has implications for current-day ecosystems – and serves as a warning that marine environments are likely more fragile than apparent.

New research, published on November 27 in a leading international journal, Nature Geosciences, suggests that oceanic anoxia played an important role in ecosystem disruption and extinctions in marine environments during the Triassic–Jurassic mass extinction, a major extinction event that occurred around 200 million years ago.

Surprisingly, however, the study shows that the global extent of euxinia (an extreme form of de-oxygenated conditions) was similar to the present day.

Carnduff Cores

Sampling of the Carnduff cores (here studied), which were drilled in the Larne Basin, Northern Ireland. Credit: Prof. Micha Ruhl, Trinity College Dublin

Historical Context of Mass Extinctions

Earth’s history has been marked by a handful of major mass extinctions, during which global ecosystems collapsed and species went extinct. All past extinction events appear to have coincided with global climatic and environmental perturbance that commonly led to ocean deoxygenation. Because of this, oceanic anoxia has been proposed as a likely cause of marine extinctions at those times, with the assumption that the more widespread occurrence of deoxygenation would have led to a larger extinction event.

Research Methodology and Findings

Using chemical data from ancient mudstone deposits obtained from drill cores in Northern Ireland and Germany, an international research team led by scientists from Royal Holloway (UK), and including scientists from Trinity College Dublin’s School of Natural Sciences (Ireland) as well as from Utrecht University (Netherlands), was able to link two key aspects associated with the Triassic–Jurassic mass extinction.

Animal Shell From Larne Basin

A core sample of ~201 million-year-old sediments obtained from the Carnduff-2 core, drilled in the Larne Basin (Northern Ireland), showing the shell of an animal that lived on the seabed shortly after the Triassic–Jurassic global mass extinction. Credit: Prof. Micha Ruhl, Trinity College Dublin

The team discovered that pulses in deoxygenation in shallow marine environments along the margins of the European continent at that time directly coincided with increased extinction levels in those places.

On further investigation – and more importantly – the team also found that the global extent of extreme deoxygenation was rather limited, and similar to the present day.

Micha Ruhl, Assistant Professor in Trinity’s School of Natural Sciences, and research team member, said:

“Scientists have long suspected that ocean deoxygenation plays an important role in the disturbance of marine ecosystems, which can lead to the extinction of species in marine environments. The study of past time intervals of extreme environmental change indeed shows this to be the case, which teaches us important lessons about potential tipping points in local, as well as global ecosystems in response to climatic forcing.

“Crucially however, the current findings show that even when the global extent of deoxygenation is similar to the present day, the local development of anoxic conditions and subsequent locally increased extinction rates can cascade in widespread or global ecosystem collapse and extinctions, even in areas where deoxygenation did not occur.”

Micha Ruhl

Professor Micha Ruhl in the lab. Credit: Prof. Micha Ruhl, Trinity College Dublin

Ruhl explained, “It shows that global marine ecosystems become vulnerable, even when only local environments along the edges of the continents are disturbed. Understanding such processes is of paramount importance for assessing present-day ecosystem stability, and associated food supply, especially in a world where marine deoxygenation is projected to significantly increase in response to global warming and increased nutrient run-off from continents.”

The study of past global change events, such as the transition between the Triassic and Jurassic periods, allows scientists to disentangle the consequences of global climatic and environmental change and constrain fundamental Earth system processes that control tipping points in Earth’s ecosystems.

Reference: “Globally limited but severe shallow-shelf euxinia during the end-Triassic extinction” by Andrew D. Bond, Alexander J. Dickson, Micha Ruhl, Remco Bos and Bas van de Schootbrugge, 27 November 2023, Nature Geoscience.
DOI: 10.1038/s41561-023-01303-2

- A word from our sponsors -

Most Popular

LEAVE A REPLY

Please enter your comment!
Please enter your name here

More from Author

Quantum Computing Takes a Giant Leap With Light-Based Processors

Researchers have developed a groundbreaking light-based processor that enhances the efficiency...

New Mission Will Unlock the Ultraviolet Mysteries of the Universe

NASA’s UltraViolet EXplorer (UVEX), set for a 2030 launch, aims to...

A New Frontier in Sustainable Pest Management for Farmers

Engineers at the University of California San Diego have developed a...

10 Years Preparing for “Armageddon”

It is not uncommon for asteroids to hit Earth. In 2013,...

- A word from our sponsors -

Read Now

Quantum Computing Takes a Giant Leap With Light-Based Processors

Researchers have developed a groundbreaking light-based processor that enhances the efficiency and scalability of quantum computing and communication. By minimizing light losses, the processor promises significant advancements in secure data transmission and sensing applications. Credit: SciTechDaily.comA team of scientists has created a reprogrammable light-based quantum processor, reducing...

New Mission Will Unlock the Ultraviolet Mysteries of the Universe

NASA’s UltraViolet EXplorer (UVEX), set for a 2030 launch, aims to enhance our understanding of the universe by conducting a sensitive all-sky survey in ultraviolet light. Credit: SciTechDaily.comNASA’s UVEX mission, launching in 2030, will conduct a groundbreaking ultraviolet light survey of the entire sky, offering new insights...

A New Frontier in Sustainable Pest Management for Farmers

Engineers at the University of California San Diego have developed a novel form of pest control using nanoparticles derived from plant viruses to deliver pesticides deep into the soil, targeting parasitic nematodes at the root level of crops. This approach promises to reduce the need for excessive...