A recent study has raised significant concerns about the depleting levels of dissolved oxygen in Earth’s water bodies, identifying it as one of the most pressing threats to life on the planet.
Importance of dissolved oxygen
Just as atmospheric oxygen is vital for terrestrial animals, dissolved oxygen (DO) is essential for healthy aquatic ecosystems, both marine and freshwater. Billions of people rely on these habitats for food and income, making the rapid decline in oxygen a critical issue.
Proposed addition to planetary boundaries
A team of scientists, led by freshwater ecologist Kevin Rose from Rensselaer Polytechnic Institute, has proposed adding aquatic deoxygenation to the list of “planetary boundaries.” These boundaries currently include nine domains, such as climate change and ocean acidification, that define thresholds within which humanity can thrive.
Impact of aquatic deoxygenation
The researchers emphasize that the decline in dissolved oxygen poses a severe threat to the integrity of Earth’s ecological and social systems. The process of deoxygenation interacts with and responds to changes in other planetary boundary processes, making it a critical area of concern.
Causes of declining dissolved oxygen
Several factors contribute to the decrease in dissolved oxygen levels. Warmer waters, a result of increasing greenhouse gas emissions, cannot hold as much oxygen. Additionally, algal blooms and bacterial growth, fueled by organic matter and nutrients from sewage, industrial waste, and fertilizers, further deplete oxygen levels. In extreme cases, this depletion has led to the suffocation and death of microbes.
The study highlights the urgent need to address this issue to protect aquatic life and the human populations that depend on these ecosystems.