Nighttime drops in ocean oxygen raise energy use in small reef fish. Repeated stress could affect reef health as oceans warm.

A dangerously low oxygen level—usually below 92%—can cause shortness of breath, confusion, chest pain, or fainting. It’s ...

Lindsay Modglin is a nurse and professional writer who regularly writes about complex medical topics, as well as travel and the great outdoors. She holds a professional certificate in scientific ...