Evaluating Oxygen Delivery with a Demand Valve

The demand valve has been promoted as an easy-to-use system that conserves the oxygen supply since it releases oxygen only when the user inhales. However, poor mask fit can lead to underperformance of the valve. Several mask configurations were studied to determine their influence on oxygen delivery.

When One on One Come Together in Greenland

Greenland is anything but green, as an ice sheet covers about 80 percent of the country. But the surrounding waters have great dive opportunities. Divers are able to get below the frozen surface and explore frigid wonders.

Diving with a Purpose in National Marine Sanctuaries

The hope is that through advocacy for underwater cultural heritage preservation, local communities across the country will discover and appreciate what marine historic sites can teach us.

DAN Member Profile: Jonatha Giddens

Ocean ecologist Jonatha Giddens, Ph.D., uses a combination of art, journaling and storytelling for her scientific endeavors. Currently, she’s using video to compute biodiversity indices.

Member to Member: Beware Complacency

While you may be an experienced diver, don’t get too comfortable. Mistakes happen to everyone…at any moment. Note these common mistakes and learn how to avoid them for your future dives.

The Alluring Hues of French Polynesia

French Polynesia is composed of 118 islands divided into five island groups, and boasts a tropical climate. It has lagoon sites perfect for novice divers.


A huge variety of diving is available throughout Malaysia, both on Penisular Malaysia and Malaysian Borneo. The water is tropical throughout Malaysia, and the area is home to exotic birds and monkeys.

Bob Talbot: A Spirit of Ocean Activism

Bob Talbot is an experienced still photographer and filmmaker — including work in the “Free Willy” movies. Read more about his journey to photography.

The Critical Instant

Behavior photography can be tricky to master — divers can either rove around searching for chance encounters or plan dives that target specific behaviors.

Ketones, Manta Rays and Extreme Environments

Csilla Ari D’Agostino, Ph.D., works in the department of psychology, and her husband, Dominic D’Agostino, Ph.D., is in the department of molecular pharmacology and physiology. The researchers returned from a NASA Extreme Environment Mission Operations (NEEMO) research and exploration mission at the Aquarius Reef Base habitat.