Air and a Spare

By Jill Heinerth

Q3/Q4 2021

No matter which alternate air source you choose, learn to calculate your air consumption and regularly practice emergency procedures. There are many ways to configure each type of redundant breathing-gas supply, but make sure your setup matches your training, gear arrangement and dive objectives. If a naysayer thinks your equipment choice is unnecessary, let them know that the difference between a fatal accident and an embarrassing incident could come down to a breath or two. Any redundancy is better than none.

The Blue Desert Conundrum

By Doug Perrine

Q3/Q4 2021

Where we encounter marine megafauna, we see only a tiny slice of their habitats and lives, which rarely includes feeding. These animals may travel thousands of feet vertically or migrate a few thousand miles horizontally to meet their nutritional needs. Some of them — sperm whales, for example — must do both: descend to depths of up to a mile or more to feast on aggregations of squid and roam across large swaths of the Pacific to avoid depleting their food resources in any one area.

Inspecting and Testing Scuba Cylinders

By Francois Burman, Pr. Eng., M.Sc., and Mark Gresham

Q3/Q4 2021

After cylinders first enter service, an annual visual inspection and a five-year hydrostatic test are required. These requirements include cylinders used for diving and other life-support applications and cover breathing air, nitrox, heliox, trimix, oxygen for decompression and argon for drysuit inflation. How are these standards mandated and enforced? What are good and safe practices?

Gas Out on the USS Monitor

By Joe Poe

Q3/Q4 2021

The current wrapped the line around my ankle and tighten like a noose. My 30-cubic-foot safety cylinder should have provided plenty of oxygen to complete my decompression stops, but I hadn’t closed the valve after charging it, so the current rushing past the mouthpiece purged the tank. I was now trapped 20 feet beneath the surface with nothing to breathe and no one aware of my peril, hoping that my mistakes with the line and my breathing gas wouldn’t be my last.

Shore Thing

By Allison Vitsky Sallmon

Q3/Q4 2021

Aside from allowing me to avoid that sunrise alarm, shore diving offers other freedoms as well: the last-minute choice of a dive site, the ability to do a two-hour dive without worrying a boat crew and the liberty to add a dive to my day if conditions allow. As an added benefit, beach diving can be quite economical compared with boat diving. And some of the most incredible sites in the world are most easily dived from the beach

Introduction to Swim Fitness

Q3/Q4 2021

Swimming is a noncontact physical activity that lets you be socially distant while still receiving many health benefits. Exercising in water can increase cardiac function, reduce blood pressure and improve muscle blood flow, respiratory function and brain function. Water reduces joint impact, so you can do high-intensity exercise with little to no discomfort from impact. Swimming targets your entire body and allows a greater range of motion for joints than land-based exercise. Blood flows more freely to your upper body, while the water supports you and lowers gravity’s impact.

Seeking an Octopus in the Wild

By Matthew A. Birk, Ph.D.

Q3/Q4 2021

Octopuses hole up in small dens, are quite excellent at camouflage and are most active at night, so not all divers have seen one on a dive. But biologist Matthew Birk, who studies octopuses, felt that never having seen one in the wild was a blemish on his career and sought to remedy the situation on a trip to Santa Catalina Island off Southern California.

Gar Waterman: The Sea Slug Sculptor

By Patricia Wuest

Q3/Q4 2021

Known for their striking colors, patterns and forms, nudibranchs are found in seas all over the world. Sculptor Gar Waterman’s fascination with these sea slugs extends beyond his aesthetic appreciation for their unique, organic form. Because most nudibranchs have a life span of less than a year and adapt rapidly to changes in their environment, they help scientists understand the impact of global warming on ocean health. With each nudibranch that he has cut, chiseled and polished from stone, Waterman hopes to communicate their quirky beauty and scientific role.

Celebrating Seagrass

By Shane Gross

Q3/Q4 2021

The benefits of protecting seagrass cannot be overstated. Seagrass purifies the water, helps protect against coastal erosion, helps sustain small-scale fisheries that support communities, and increases fish populations and biodiversity. It sequesters much more carbon per area than terrestrial forests and reduces ocean acidification. Healthy seagrass means a healthier ocean.