If you have ever been in a smoke-filled room and wanted nothing more than to go outside and get a breath of fresh air, you can relate to the experience of your average flounder.
It’s floundering.
Fish don’t breathe air, but they still take in oxygen dissolved in the water around them, and if those oxygen levels drop too low, they can strangle.
When we try to think about the effect of the climate emergency on oceans, we tend to imagine warming seas, bleaching corals, algae blooms, super-hurricanes, and inundating coastlines. We don’t often think about oxygen. And yet, major extinction events in Earth’s history have generally been associated with oxygen-starved oceans, most often during climate change epochs.
In the process of absorbing a majority the excess carbon dioxide we’ve produced, the open ocean gave up an estimated 2 percent, or 77 billion metric tons, of its oxygen over the past 50 years. That is an astonishing number, but one seldom noticed unless you are a water-breather.
As a result, oxygen-minimum zones (OMZs) expanded to cover areas in aggregate about the size of the European Union (4.5 million square kilometers). Anoxic dead zones (devoid of oxygen) have more than quadrupled. For your average fish, this means trying to steer clear of OMZs and dead zones, mainly along the coasts where…