ECO PRO continued the neuston community of tiny organisms – plays a crucial role in the planet’s “breathing” process. For divers on the surface, this boundary might seem insignificant. However, it’s where climate-regulating activities, such as carbon ab- sorption and oxygen release, occur. Understanding it is es- sential for global climate science – and for understanding how your actions on land impact the sea. As divers, we often focus on marine biology, but chemistry forms the foundation of both biological and physical processes in the ocean. From the clarity of your mask to the composition of your gas mix, and from coral reef health to the future of our planet, chemistry plays a vital role in the diving experience. Understanding even a few of these chem- ical principles helps divers become more knowledgeable – and more empowered – guardians of the underwater world.
Buoyancy Weight Conversion Formula New divers often ask if there’s a formula by which they can convert the amount of weight required to obtain neutral buoyancy in freshwater to the amount needed to dive in sea- water and vice versa. So, for you math geeks: • From Fresh Water to Salt Water: Seawater weight = Fresh- water weight × (1.025 / 1.000) • From Salt Water to Fresh Water: Freshwater weight = Saltwater weight × (1.000 / 1.025) A quick rule of thumb for most recreational divers is to add ~2.5% of your total body weight and gear weight when transitioning from freshwater to seawater, and subtract ~2.5% when going from seawater to freshwater. This gen- erally means adding 2–4 pounds (1–2 kg) of lead. But remember that these calculations and estimates have caveats. It assumes standard ocean salinity (~35 ppt) and similar exposure suit and gear. And bodies of water like the Red Sea or Persian Gulf have much higher salinity and re- quire even more weight. Most importantly, regardless of what pre-dive calculation is used, a proper buoyancy check is always recommended – especially in new environments.
[Editor’s note: This article is a brief synopsis of Chap- ter Two: The Chemistry of the Sea from the author’s re- cent book, Beneath the Blue Planet: A Diver’s Guide to the Ocean.]
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