Researchers have discovered a self-feeding process of oxygen depletion in the oceans

The problem is serious because it harms the marine food chain, and ultimately ours as well. They compared the current process with a similar process that occurred 500 million years ago. The results are not encouraging

Five hundred million years ago, the Cambrian Steptoean positive carbon isotope excursion (SPICE) event caused a dramatic drop in oxygen levels in the oceans. Similar signs of this are already seen today near the coasts, precisely in places that are supposed to be teeming with marine life.

Researchers from the University of Copenhagen describe how widespread anoxia (lack of oxygen conditions) in the ocean developed during this event and its possible consequences today.

In their study, titled "Increasing Oxygen Loss to Ocean Shores – Insights from the Cambrian SPICE Event," published in One Earth, the researchers found that a chain reaction involving the recycling of phosphorus from ocean sediments played a major role in the decline in oxygen levels in the oceans.

"In anoxic conditions, phosphorus is more efficiently released from sediments, which further depletes oxygen levels and extends anoxia to a global scale," said Associate Professor Thies Wu. Dahl from the Globe Institute, a senior researcher in the study.

He added, "This intrinsic positive feedback response led to rapid and prolonged marine anoxia. The study warns that the danger of this chain reaction still looms over today's oceans, where human activities may affect nutrient dynamics in ways that raise the risk of creating increasingly anoxic conditions. Coastal areas, especially , can be susceptible to anoxia that can spread on a wide scale."

While anoxia on a global scale is not an immediate threat today due to limited phosphorus resources and high atmospheric oxygen levels, the study highlights the importance of understanding nutrient dynamics and sedimentation processes, especially in coastal areas. These insights are critical to managing the health of marine systems and their animals.

By comparing geological and modern marine systems, this study provides valuable insights into the possible evolution of ocean chemistry today. While emphasizing the importance of the geological context, the research aims to improve forecasting models and guide policy decisions to maintain marine ecosystems and ensure their resistance to ongoing environmental changes.

for the scientific article

# ?️ Suggested tags:

Ocean Oxygen Decline, Ocean Anoxia, Oceanographic Research, Cambrian SPICE Event, Phosphorus Recycling, Nutrient Dynamics, Modern Oceans, Ocean Pollution, Marine Systems Health, Ocean Chemistry, Climate Change, Environmental Science, University of Copenhagen