Not in Denial

HAVING DONE THOUSANDS OF DIVES since I started in 1964, primarily off the coast of North Carolina, the shipwrecks and dive profiles there are familiar. Overall conditions couldn’t have been much better on this particular day — calm, clear seas with barely a current. We planned on two reverse profile decompression dives at an offshore […]

When History Seemingly Repeats Itself

IN 1983-84, REEFS THROUGHOUT THE CARIBBEAN, FLORIDA, AND BERMUDA experienced one of the greatest mass mortalities of a marine species ever recorded when an unknown waterborne pathogen killed more than 98 percent of the Diadema sea urchin population.1 In February of this year, divers in St. Thomas noticed many of the Diadema were suddenly no […]

Diving After Brain Surgery

I RECENTLY UNDERWENT BRAIN SURGERY. The surgery was successful, but now part of my skull has been replaced with mesh. My neurosurgeon is brilliant but does not know how the surgery may affect my diving. Am I still able to dive? Should I limit myself to a certain depth, or should I only snorkel?   While […]

Sherri Ferguson

SHERRI FERGUSON, MSC, IS THE LAB MANAGER at Simon Fraser University’s hyperbaric chamber, located at an altitude of 1,200 feet on Burnaby Mountain in the outskirts of Vancouver, Canada. She is a scientist working in aerospace and dive research, an experienced recreational, technical, and commercial diver, and a mother. How did you get into diving? […]

Alert Diver Q3 2022 Researcher Profile

Emergency Oxygen

IT WAS A BEAUTIFUL, WARM SATURDAY IN THE PACIFIC NORTHWEST. We were conducting two checkout dives for an advanced open-water course at a popular dive site in Puget Sound. I had just gotten some divers out of the water, and we were debriefing onshore as divers from a basic open-water class exited the water with […]

emergency oxygen DAN first aid courses 3.0

Teaching Rescue: Am I Qualified?

WHEN ASKED TO DESCRIBE THEIR FAVORITE COURSE, many divers will discuss the challenges and triumphs they experienced during their rescue class. Instructors often describe rescue as the most rewarding course they teach. It is often the first course in which divers begin thinking about others more than themselves, so it’s little surprise that it stands […]

dive rescue course at DAN

Trouble in Galápagos

DAN EMERGENCY SERVICES RECEIVED A CALL via satellite phone from a liveaboard anchored off a remote island in the Galápagos. A DAN member was concerned about their bunkmate exhibiting symptoms following the day’s dive activities. The diver had completed four dives that day. Although she began to show symptoms following the second dive, the inexperienced […]

Oxygen Cleaning of Dive Gear: A Two-Part Series

IN THE PREVIOUS ARTICLE, we settled on the recommendation that equipment used to control any breathing gas mix containing 25 percent oxygen and above at typical scuba cylinder pressures should be designed and considered suitable for oxygen use. Possible debates aside, we’ll examine what oxygen cleaning means. How often should gear be oxygen cleaned, and […]

Popping the Question: What is a DSMB?

SURFACE MARKER BUOYS (SMBS) AND DELAYED SURFACE MARKER BUOYS (DSMBS) are common and essential safety devices. These brightly colored, inflatable tubes, sometimes called safety sausages, are critical pieces of equipment that divers should take on most dives. Divers most often use them as signaling devices to mark their locations below the surface and alert boat […]

Alert Diver Q3 Dive Gear