The Earth is in crisis — a reality made increasingly clear by intensifying heat, drought and storms, worsening pollution, land stripped of forests, and the ramping up of the sixth great extinction. But some scientists say we’re failing to prioritize a critical Earth change that is accelerating in the modern world and that helped drive past global extinction events: aquatic deoxygenation. In 2023, scientists suggested that anoxia, the lack of dissolved oxygen in a water body, played an important role in ocean ecosystem disruption and extinctions during the Triassic-Jurassic mass extinction around 200 million years ago, while others say it contributed to the “great dying” of the Permian extinction 50 million years earlier, which wiped out 90% of all marine species. Today, human-caused hypoxia (reduced oxygen levels), due increasingly to synthetic agricultural fertilizer pollution and climate change, annually helps create vast dead zones in the Gulf of Mexico, Baltic Sea, East China Sea, and estuaries, lakes and streams around the globe. Now, a new perspective piece in Nature Ecology & Evolution seeks to add aquatic deoxygenation of both fresh- and saltwater ecosystems to the planetary boundary framework, a theory currently used to define the safe operating limits for Earth’s natural systems. Red tide under the Astoria Bridge, Oregon, U.S. Image by Alex Derr via Flickr (CC BY-NC-SA 2.0). Natural systems out of balance In 2009, a team of international scientists proposed the planetary boundary framework, a theory defining nine interconnected biophysical and biochemical processes: natural systems that regulate Earth’s stability…This article was originally published on Mongabay
The post As waterbodies lose oxygen, are we breaching a potential planetary boundary? first appeared on EnviroLink Network.