The Oceans are Getting Starved of Oxygen

Supplies of dissolved oxygen in bodies of water across the globe are dwindling rapidly, and scientists say it's one of the most significant risks to Earth's life support system.

Dissolved oxygen in water is essential for healthy lakes, rivers, and seas, not only for the health of the planet but the lives of people; we rely on them for food and income. It's a serious concern.

The concentration of dissolved oxygen in water has dropped for several reasons. Warmer waters can't hold as much dissolved oxygen, for instance. With greenhouse gas emissions rising and air and water temperatures rising above their long-term averages, surface waters are becoming less able to hold on to oxygen.

Aquatic life can also deplete dissolved oxygen faster than it is replenished. Algal blooms and bacteria triggered by increased organic matter and nutrients from agricultural and domestic fertilizers, sewage, and industrial waste quickly soak up dissolved oxygen.

Aquatic deoxygenation is also driven by the increasing density differences between layers in the water column. The cause is surface waters warming faster than deeper waters, and melting ice is decreasing the ocean's surface salinity thanks to density differences.

Without dissolved oxygen, virtually no life can survive in our oceans, lakes, and rivers. Nations - politicians, that is - aren't moving fast enough to stop the problem. It's not just one more thing we must worry about; it's one more problem we must solve if life on Earth is to survive, one of the subset of problems advanced by burning fossil fuels.

- Based on an article in Science Alert