New research led by scientists at the University of Bristol has shown that the feedback mechanisms that were thought to keep the marine nitrogen cycle relatively stable over geological time can break down when oxygen levels in the ocean decline significantly.
The nitrogen cycle is essential to all forms of life on Earth - nitrogen is a basic building block of DNA.
The marine nitrogen cycle is strongly controlled by biology and small changes in the marine nitrogen cycle have major implications on life.
It is thought that the marine nitrogen cycle has stayed relatively stable over geological time due to a range of different feedback mechanisms.
These feedback mechanisms are called ‘the nitrostat’. However, exactly how the global marine nitrogen cycle and the associated feedback mechanisms responded to past severe changes in marine oxygenation is not well understood.
The team used a data-constrained earth system model to show show that under these deoxygenated conditions the ocean can become extremely depleted in nitrogen as the total bioavailable nitrogen inventory collapses relative to phosphorous.
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