U N D E R C U R R E N T   O N L I N E    U P D A T E
F O R    N O N – S U B S C R I B E R S

Undercurrent — Consumer Reporting for
the Scuba Diving Community since 1975
www.undercurrent.org

Dive News

February 9, 2010

You have received this message because you have signed up on our website to receive this email or you are a former subscriber or Online Member of Undercurrent . If you had a username associated with this email address, it is Removal instructions are below.

Subscribers/Online Members can get all the articles
from the current issue of Undercurrent here

Mares is Recalling All Nemo Air Computers: If you’ve got one, contact your dealer now. Mares issued a recall last summer for the slow-leaking O-rings on the Nemo Air computer’s Quick Connector hose, but it turns out the replacement O-ring issued wasn’t the solution. On February 1, Mares announced another recall for the entire hose. “We designed a new quick disconnect system to replace it,” Mares’ national sales manager Steve Lamphear told Undercurrent. All Nemo Air dive computers need this replacement so contact a Mares dealer to get the hose replacement, free of charge. If you want Mares to do the replacement, call Customer Service at 800-874-3326 and give them your computer’s serial number for shipping info.

Undercurrent Blogs: If you haven’t been following our blogs, you’ll get plenty of information, laughs and education from guest bloggers like Bret Gilliam, the deepest air diver ever; Doc Vikingo, peripatetic columnist; Burt Jones and Maurine Shimlock, who just completed an excellent book on Raja Ampat; John Bantin, the equipment editor for Diver magazine; and many, many more. Go to Undercurrent and click on blogs.

And A Regulator Recall From TUSA: It’s taking back RS-670 regulators sold between May and September 2009 because loosening of the BLC plug on the first stage may cause a high-pressure leak. Affected units have first stage serial numbers between 22 and 29, 31 and 103, 637 and 676, 708 and 716, and 737 and 776. Take your regulator back to the dealer, or contact TUSA at info@tusa.com or call 800-482-2282 to mail it back for repair, covered under warranty.

Great Free Online Dive Medicine Book: Carl Edmonds, co-founder of Australia’s Diving Medical Centre, alerted us that his formerly out-of-print book Diving Medicine for Scuba Divers has just been updated for 2010 and, better yet, is available to download for free online: (http://www.divingmedicine.info/divingmedicine/Welcome.html). This classic book, which Edmonds co-authored, deals with dive-specific health issues, their causes, first-aid and prevention. You can download any of the 43 chapters, from Panic and Fatigue to Drugs and Diving, one at a time, or the entire book. Edmonds encourages you to download his book onto a CD/DVD to take with you on your next dive trip, or just pass on to fellow divers.

Coral Reefs Need Your Foreign Currency: Admit it. You’ll never use those foreign bills in the bottom of your drawer, so send them to us to convert into greenbacks and apply them to a project to save our oceans and reefs. It’s tax-deductible and I’ll send you a receipt for your contribution greater than $50 (Undercurrent is a 501c3 organization and contributions are tax-deductible). So far, we have outfitted a sailboat so rangers can stop night poachers on Belize reefs, and helped build a school in Fiji, for which the chiefs established marine-protected areas totaling 3,010 acres and a 4,752-acre forest preserve. Send the bills to me: Ben Davison, P.O. Box 3020, Sausalito, CA, 94965. And feel free to include a tax-deductible personal check made out to Undercurrent as well. If divers don’t save the reefs, who will?

A New Online Guide for Underwater Photographers: Here’s a new site underwater photographers of all levels can check out for tips. Underwater Photography Guide (http://www.uwphotographyguide.com) offers an online tutorial book from Santa Monica-based diver and photographer Scott Gietler – check out the Chapter Index to get straight to info on wide-angle optics, image sharpness, post-processing and more. Every week, Gietler posts new articles on photography theory and technique, and equipment reviews. Or sign up for a monthly e-mail newsletter. All information is free to read.

Kudos To Louie Psihoyos And The Cove: Psihoyos, the National Geographic photographer turned filmmaker, has been winning a slew of awards for his feature-length documentary, a stealth effort by divers to document the dolphin slaughter at Taiji, Japan. The Cove won Best Documentary at the Critics Choice Awards, and the Directors Guild of America named Psihoyos the best documentary director of 2009. Now The Cove is an Oscar nominee for Best Documentary. See if it wins on March 7; and The Cove is now available on DVD. P.S.: I helped Louie raise $20,000 to subtitle The Cove in Japanese for distribution in Japan.

What You’re Missing in the February Issue: Subscribers and Members can download the entire issue or individual articles. , and read about:

• The best diving on California’s Catalina Island
• Grand Cayman Officials Say Alcohol and Stingrays Do Mix (Available to the public)
• A “fishy” spot on Baja California’s East Cape
• Add this African dive site to your bucket list
• “Star Trek” wetsuits — no kidding
• Ben Davison’s report on Copenhagen’s climate change conference (Available to the public)
• Gear expert John Bantin picks the fastest fins
• The embarrassment that made a diver lose 90 pounds
• A San Diego dive shop with a dark history

Read an Issue: I want you to see a full copy of Undercurrent’s monthly newsletter; you can do so on our home page at Undercurrent. Right now, if you sign up to have it delivered to your email address each month, I’ll send you a free, 480-page, 2010 Travelin Diver’s Chapbook, chock full of reviews of hundreds of resorts and liveaboards worldwide – go to http://www.undercurrent.org/cbook2010 (previous Online Members can get the same offer and keep their old username/password by going to https://www.undercurrent.org/secure/UCnow/OMaccountCenter.php?omcoupon=c14 )

My Report From The Copenhagen Conference: I attended the entire U.N. Climate Change conference, held in Copenhagen in December, taking in dozens of presentations and talking to experts about the environmental impact on the oceans. Will any significant changes come from it? Read my report for free in the February issue – go to Undercurrent and click on “A Diver’s Report from Copenhagen.”

Diving the World: A Guide to the World’s Most Popular Dive Sites: Authors Beth and Shaun Tierney describe 220 dive sites in 19 nations, along with site maps, country reviews, seasonal dive information, destination ratings, preferred dive operators and liveaboards, good travel information and hundreds of color photos. If you’re interested in the Caribbean, you won’t find much besides the Yucatan, Honduras, Belize and Grenada. But the key countries in the Pacific and Indian Ocean are all covered. If you’re an adventurous traveler, there’s a lot of good reading here. Go to Undercurrent, click on “Books” and buy it through us; you get it from Amazon.com and our profits go to conserve coral reefs.

Do Alcohol and Stingrays Mix?: According to Grand Cayman officials, they can with no detrimental effect. In December, they granted liquor, music and dancing licenses for a floating bar to be built on the waters near Grand Cayman’s Stingray City. Read points of view from both the protestors and the businessman building the bar in our article “Grand Cayman Officials Say Alcohol and Stingrays Do Mix,” available for free at Undercurrent.

Coming in Future Issues:

• The isolated isles of Honduras: Cayos Cochinos,
• The WWII wrecks of Saipan,
• Buddys on Bonaire,
• Secret diving in Turkey,
• A new Sea of Cortez liveaboard,
• New dangers of rebreather diving
• Digital camera tips for good underwater photos
• Why divers are hanging up their fins
• Join the hunt for lionfish in the Caribbean
• The extremes one diver took to get customer service from Scubapro
• and much, much more..

Ben Davison, editor/publisher
Contact Ben

Website News

Diving Discounts: We have a number of special deals from dive operators worldwide on our website’s Special Offer page that could be just what you’re looking for. These include:

• 10-20% discounts on M/Y Manthiri (Maldives),
• $850/wk diving in Utila, Honduras,
• A write-your-own diving safari in Bal especially for UW photographersi, and
• Buying a large villa with pool in Bali in front of one of the world’s best dive spots.

See them all here and check back there periodically as new offers are being added constantly.

Get Notified of New Divers’ Blogs: See what you’ve been missing from leading industry pundits: John Bantin, Bret Gilliam, Ben Davison, Bob Halstead, Burt Jones & Maurine Shimlock, and Doc Vikingo — there’s lots of provocative posts since our last update. If you want to keep up with these, we can now notify you by email whenever there’s a new post (1-2/week) — just sign up here

Dave Eagleray, webmaster

Note: Our travel writers never announce their purpose, are unknown to the destination, and receive no complimentary services or compensation from the dive operators or resort. Dive trips listed in our emails must be offered by a well-regarded operation that has been reviewed positively by our readers. The operator must include a special offer for Undercurrent subscribers and supporters. Undercurrent is a 501 (c)(3) not-for-profit organization and in some cases the operator has made a donation.

HELP A BUDDY OUT:
forward this message to another diver here: this link

Chapter 4

CO2 Retention in Scuba Diving

CO2 retention with it’s attendant dangers of death from convulsions and hypoxia (low oxygen level) is primarily of concern to the scuba diver due to “skip breathing”. Other sources of CO2 retention are breath-hold diving, breathing in a sealed environment, faulty regulator, exercise at extreme depth and using contaminated air.

Symptoms include rapid respiration in 4-6%, rapid pulse rate, shortness of breath in 7-10% and convulsions and unconsciousness in 11-20%.

The CO2 level in the blood is unchanged by the ambient pressure (i.e., the depth) per se, since the partial pressure of carbon dioxide in a scuba diver’s blood is a function only of metabolism and the rate and depth of breathing - the same factors that determine blood CO2 concentration on land.

All of the CO2 that’s developed during breathing underwater is exhaled in the bubbles from scuba apparatus and does not increase with depth as do other gases, such as nitrogen, oxygen, CO and hydrocarbons. Abnormal carbon dioxide accumulation in the blood can occur from too high a level of metabolism (such as from exercise at depth) and/or inadequate breathing (usually not breathing deep enough or skip breathing). The medical term for high carbon dioxide in the blood is hypercapnia; when the level is high enough it can cause “CO2 toxicity,” which can lead to shortness of breath, headache, confusion and drowning (depending on severity).

Elevated CO2 levels play a significant role in oxygen toxicity and in nitrogen narcosis.

The acceptable CO2 level for diving operations is 1.5% surface equivalent (10.5 mmHg); the acceptable level for hyperbaric chamber operations is one that allows a vent schedule of 4scfm/person displacement.

With the increased usage of closed circuit scuba diving, mainly by the military-but recently by more and more civilian divers, there is the possibility of hypercarbia (high CO2 levels), among other medical considerations.

Signs and symptoms that need to be observed are hyperventilation, shortness of breath and tachycardia (rapid heart beat), headache and excessive sweating, mental impairment and finally , unconsciousness.

This hypercarbia comes about due to malfunction of the CO2 absorbent canisters and can be avoided by decreasing the exercise rate, watch out for the operating limits of the canister, checking for leaks at the start of the dive and not reusing the absorbent.

==============================================================================

=================================================

---

Divers often donate blood and need to know when to resume diving. This article is meant to provide information to help answer those questions. This information should apply to any type of diving since the effect depends on the hemoglobin in the red blood cell mass rather than the partial pressures of gases.

How long must a diver wait after blood donation before diving?

The donor’s body replenishes the fluid lost from donation in 24 hours. If not anemic (Hgb<12 Gm/dl)a person can dive in 24 hours after blood donation. It may take up to two months to replace the lost red blood cells. Whole blood can be donated once every eight weeks. The most important part of the blood to the diver is the red blood cell, responsible for the transport of oxygen to the tissues. The fluid part of blood is replenished in about one day. If the diver waits 24 hours and has a normal hematocrit, then diving should be allowed.

Red blood cells are perhaps the most recognizable component of whole blood. Red blood cells contain hemoglobin, a complex iron-containing protein that carries oxygen throughout the body and gives blood its red color. The percentage of blood volume composed of red blood cells is called the “hematocrit.” The average hematocrit in an adult male is 47 percent. There are about one billion red blood cells in two to three drops of blood, and, for every 600 red blood cells, there are about 40 platelets and one white cell. Manufactured in the bone marrow, red blood cells are continuously being produced and broken down. They live for approximately 120 days in the circulatory system and are eventually removed by the spleen.

Is there a way to donate blood products and still be able to dive immediately?

Yes, through apheresis. This is the process of removing a specific component of the blood, such as platelets, and returning the remaining components, such as red blood cells and plasma, to the donor. This process allows more of one particular part of the blood to be collected than could be separated from a unit of whole blood. Apheresis is also performed to collect plasma (liquid part of the blood) and granulocytes (white blood cells).

Is there a way to shorten the time interval before red blood cell replenishment after blood donation?

Yes – Approximately 10 percent of body iron stores are removed with each donation. When appropriate, iron supplements can be prescribed for patients making donations to help increase red blood cell count. Erythropoietin, a hormone, can also be given to stimulate the bone marrow into producing more red blood cells.