Mouths Full of Eggs

Eggs are a dinnertime delicacy in reefs around the world, which means protecting nests is hard work. Ironically, the safest place to hide eggs may be in the mouth.

A cardinalfish has its mouth full of orange eggs

Oxygen Sensing in Rebreather Diving

Reliable measurement of oxygen is the technology that makes mixed-gas closed-circuit rebreathers (CCRs) possible. The first digital solid-state CCR sensor was made available in Spring 2017, and has greater accuracy and reliability.

A diver photographs a temperature logger that is lodged into a coral

An Emergency Ascent Just in Time

Dive safety experts now advise divers to always dive with their tank valves completely open — not turned back a half or quarter turn. Are you up to date on the rules? Read one diver’s story.

An unconscious diver floats near coral

Member to Member: A Reef in the Living Room

Aquariums can house your own slice of indoor reef life — complete with colorful fish, corals and spunky crabs. Follow these tips to create your perfect aquarium.

A big saltwater fish tank stands proudly in a living room.

A Free-Flowing Failure

Contrary to what you might expect, air will escape from a low-pressure hose faster than from a high-pressure hose because of the low-pressure hose’s wider opening.

Contrary to what you might expect, air will escape from a low-pressure hose (left) faster than from a high-pressure hose (right) because of the low-pressure hose’s wider opening.

DAN Member Profile: Jim W. Bunch

DAN member, diver and author Jim W. Bunch talks about discovering and exploring underwaters wrecks on the shores of North Carolina.

In a black-and-white image, Jim Bunch inspects a shipwreck

High on Mercury

Grouper populations are on the rebound thanks to protection efforts. But a major threat to these fish remains: mercury.

A school of angry-looking grouper

Due Diligence for Parents of Young Divers

Parents often express reservations or concerns about going on dive vacations with their kids. But it’s a joint reasonability from both parents and dive operators.

A group of children sit on a walkway, with their hands raise, taking a scuba diving class