Valparaiso, CHILE—The Chilean government on Monday announced that it has created the largest marine reserve in the Americas by protecting an area hundreds of miles off its coast roughly the size of Italy.

One in four people have an opening between the left and right chambers of the heart – called a Patent foramen ovale or PFO. Normally this is not a problem, a flap covers the opening and generally remains closed because of greater pressure in the left chamber than the right. In scuba divers though, it is a worry.

After and whilst ascending from a dive, nitrogen bubbles are formed in the blood of a diver’s veins and carried back to the heart. In a diver with a PFO, the bubbles can pass to the left chamber of the heart and be carried in the arteries back around the body. If they get into the tissues then the diver might get decompression sickness (the bends), even when diving within the normal decompression limits.

One of the treatments for a PFO is to close it using a catheter based procedure. A catheter is a flexible hollow tube which can be used to move a closure-device in place in the heart. In a study available this week in the journal, JACC: Cardiovascular Interventions, doctors report that closing a PFO in this way completely eliminates arterial bubbles after a dive. This compares to a control group where after an 18 m dive 32% of them had bubbles in their arteries, and after a 50 m dive 88% exhibited arterial bubbles. No difference was found in the presence of bubbles in veins in either groups.

The dives were simulated in a hyperbaric chamber: 34 divers “dived” to 18 m for 80 min, and 13 divers to 50 m for 20 min.

Removal of large predators through fishing has been suggested to help the populations of smaller fish.

An international team of scientists tested this assumption and found that no-take Marine Protected Areas (MPAs) benefited all major groups – higher carnivores like sharks and groupers, benthic carnivores that live near the bottom like butterflyfishes, planktivores and herbivores. Their biomass was 40-200% greater where large predators were left alone compared to open-access areas where fishing took place.

Zippers How well a zipper keeps out the cold depends on its seals. some use double — or even triple — overlapping smooth-skin with a long or inter- locking internal flap. Generally, a waterproof chest or shoulder zip will be drier — though more restrictive and harder to don and doff— than a nonwaterproof vertical rear zip.

Diving Style If you always wear a hood, consider a suit with one that’s attached. If you need maximum insulation, look at the thickest suits. If mobility is important, choose a suit that uses thinner materials in the arms and legs.

Seals Today’s suits come with more seal types than color choices – smooth-skin o-rings, double smooth-skin zippered cuffs, single smooth- skin cuffs, internal gaskets, etc. Personal preference and perfect fit are the keys to finding the best type of seal for your suit.

Materials Manufacturers often have proprietary names for their suit materials; you’ll find that one neoprene might be a little stretchier, or another is a bit denser. the bigger differences are in how the materials are used, and how the suits are shaped and put together.

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