Anyways; what was going through my mind was how much my income actually was compared to what I could earn elsewhere, or rather; what I would have to earn elsewhere to be able to get for my funds there, what I get for my funds here. And this is how I calculate. I divide the compared price with my salary and then I take the price for the same thing in Sweden and multiply that with the sum from the when I divided my Egyptian wages and badabim badaboom; I’ve got the salary I’d need in Sweden to get the same value for money as I do here. Now imagine doing the same calculations compared to London, Los Angeles, Paris or some place that is really expensive…

The dive industry is not making you rich. It won’t get you a fat number account on the Caymans… (Well it did get me the Cayman number account but it’s slimmer than the book listing successful peace-negotiations in the Middle East. And I don’t even remember the PIN-code to my Cayman bank-card so I can’t use the money anyway.) You don’t earn that much on diving. It puts bread and butter on the table, but there are no extra benefits like dental or retirement funds. However my life is richer than if I would earn twice or even five times the money sitting in an office or working the floor in any plant. I don’t work to be able to afford to do what I like during a few weeks holiday. I get paid to do what I love and for me that is more rewarding than all the money I’d potentially earn from a 9-5 job.

My basic salary is 900€ plus what I get in tip and commission; around 100€/week. This adds up to around 1.300€/month. For this money I can live like a prince in Egypt and I seldom have to say: “No I can’t afford that”. On top of this I eat for free on the boat 6 days a week. If I would have the same salary living in Sweden as I do here in Egypt I would probably consider myself fairly well-off. Though, how much that would be depends on how you count. Lets just for fun make a few calculations.

To get the same amount in my bank account after tax as I get in my hand here my salary before tax in Sweden would be around 2.000€. That’s not a lot of money so here comes a few additional calculations. All of these numbers are calculated salary after tax!

If I would spend the same percentage of my funds on food in Sweden my salary would have to be better. I can go out and get myself a whole BBQ chicken with rice, salad, a coke and a smile for 7 Egyptian pounds. That’s less than 1€. If I go to Mac Donald’s I get a large size menu for 25 Egyptian pounds. That’s less than 3:50€. I can go out and have a luxury dinner at a nice restaurant and the bill will not exceed 120 Egyptian pounds. That’s less than 17€. I made a quick calculation of the top of my head that I would have to earn about 4.000€ after tax in Sweden to use the same volume of my monthly wages compared with the food prices we have here.

To have the same sized part of my pay check go to accommodation/rent my salary would have to be even better. I have an 80m2 penthouse with 100m2 balcony/roof terrace, sea view, two bedrooms and living room in an absolute prime location. I’m not sure how much one of those would cost in Sweden and of course that would depend on location, but with an educated stab in the dark I’ll put a 1.000 € price tag on a equivalent accommodation along the coast in Sweden. And then I think I’m careful. This means that I would have to earn around 6.000€ after tax for that to be the same percentage of my income.

They are really great especially if you are having to chase students. The foot pocket is very comfortable and not to rigid.  The different settings make them great for easy dives or for hard currents. They are easy on the legs, to me, even at the tightest setting. It was even easy to change the setting underwater with gloves. I have used them on a few regular dives with students and on some drysuit dives. They were still powerful with my drysuit.

Plus you’ve gotta like the “mermaids don’t like competition video”!

Kate Bradshaw, writing for Maui Time, estimates the massive floating plastic patch is twice the size of Texas:
The Great Garbage Swirl http://www.mauitime.com/Articles-i-2009-01-29-68584.113117_The_great_garbage_swirl.html

Please invest seven minutes to watch this riveting presentation concerning this deadly problem by Captain Charles Moore, who is credited with having discovered this symptom of a planet gone mad: Captain Charles Moore’s Presentation http://www.ted.com/talks/capt_charles_moore_on_the_seas_of_plastic.html

The article below, by Jacob Silverman, provides additional information, and links to numerous sources illustrating how humans have turned the world’s largest ocean into the world’s largest “landfill”.
Pacific Ocean = World’s largest “Landfill” http://science.howstuffworks.com/great-pacific-garbage-patch.htm

Finally, this Wikipedia link provides detailed diagrams of how the ocean currents distribute out plastic waste into massive patches:
Wikipedia Link To Ocean Plastic http://en.wikipedia.org/wiki/Great_Pacific_Garbage_Patch#Plastic_photodegradation_in_the_ocean

What We Can Do:

1. Become informed. Read the above links or explore on your own.
2. Support conservation efforts toward recycling plastics.
3. Use less plastic! For example, don’t purchase water in those small bottles, which clog landfills or end up floating in the ocean. Instead, fill re-usable containers, and/or install home-based water purification systems.

This Chris Jordan photo (http://www.chrisjordan.com), showing a dead albatross on Midway Atoll, illustrates the point. Clearly seen in the decayed bird’s stomach are a plastic cigarette lighter, bottle caps and miscellaneous plastic trash.

Albatross, killed by ingesting floating plastic

There are 70 species of dolphins and whales in the world and it is estimated that approximately 25 visit the waters of Costa Rica. This is for a variety of reasons, whether they are migrating, mating, birthing or feeding, the warm waters with currents bringing plentiful food are an obvious attraction. Some of the more frequent visitors are false orcas, spinner dolphins, pan tropical spotted dolphins and the humpback whale.

One of the most prolific and recognizable of the whales species is the humpback whale which is also Costa Ricas most frequent whale visitor. With a size of up to 50ft and a weight of approximately 24 – 40 tonnes that are incredible to behold and here in Manuel Antonio we are lucky enough to see them during both seasons. Whilst not being lucky enough to have seen them underwater whilst diving, I have been lucky enough to be serenaded by them on numerous occasions. Not what you expect to hear,sometimes, the mixture of long deep bellows, and high pitched singing is eerie yet beautiful. The hardest thing when you start hearing them, especially when it is a faint sound, is communicating to your fellow divers what they are listening to as many, won’t immediately recognize the sound.

On the surface intervals and trips to dive sites we can be lucky enough to run into humpbacks, for example just 4 days ago. On our way through the park our captain noticed some spray off of the bow. It was a group of 3, 2 adults and 1 calf. They then proceeded to travel pretty rapidly away from us, but not before the calf decided to breach a couple of times. I’m sure he knew he had an audience!! Before my battery ran out  managed to get a sneaky shot of a disapearing tail!

Dolphins are also a regular visitor to the Manuel Antonio National Park and the pacific coast in general. Pretty much every afternoon we will get to see a school of the Pan Tropical spotted dolphins feeding just off of the coast. Pan Tropical spotted dolphins are one of the smaller species of dolphin and when they are feeding, they target one of their favourite foods, flying fish. Easiest way to spot a group is to watch for the brown booby birds who like to hang out above the hunt and pick off any unfortunate escapees! Diving at Cano island, which has  many whale and dolphin visitors, I have been lucky enough to dive with dolphins. One of my mos memorable encounters was at the deep sea pinnacle Veinte Seis. Hearing them throughout the dive, we headed up the down line for a safety stop. Diving offshore is always fun as you are diving in blue, blue water with nothing around. Out of the distance, a group of around 10 dolphins appeared and they took an interest in us and decided to hang out with us throughout the safety stop, which we subsequently decided to extend to around 15 minutes to enjoy their company!

As the humpback season is drawing to a close next month I need to make sure I get as many encounters as possible before the lull!

Many divers across the Northern Hemisphere, especially in these cold winter months (as I write this, I am in shorts and a t-shirt ), are thinking, “I’m getting pretty sick of this low-visibility quarry and this dry suit.” Their diving fantasies are reaching fever pitch, imagining a place where the sun is shining, the only temperature they can find in the 30s is that of their mixed drink, and the underwater world provides rich, colorful vistas, chock full of coral and teeming with tropical fish.

Welcome to my home. Believe it or not, I am not describing the Bahamas, or even the Mediterranean. In fact, most of you reading this don’t need a passport or to spend a full day on a plane to get here.
Welcome to Florida.

Most divers know there is some diving here, and have probably heard of the Florida Keys- North America’s only barrier reef, and the third largest in the world.

What you may not know is that Florida is home to a wide variety of diving environments and attractions.
From the world famous Molasses Reef in Key Largo (great for snorkelers, too!), to 3 of the largest artificial reef shipwrecks in the world (the Oriskany, Vandenberg, and Spiegel Grove), to the excellent spearfishing of the both east coast and the Gulf Coast, we have it all.

Then there are the crystal-clear freshwater springs of North Central Florida. The next time you pick up a room-temperature bottle of spring water, imagine diving in that. With that visibility and temperature. Year round. Add in some manatees, a gentle-giant type mammal, or even some real life mermaids (don’t believe me? Search for Weeki Wachee Springs)!

If you’re a technical diver you will love the aircraft carrier Oriskany with the flight deck at a depth of 145 feet. It has a fitting home off the coast of the Panhandle city of Pensacola, near the Navy’s flight school. Or there is always the hundreds-of-miles-long Wreck Treck – a veritable all-you-can-dive buffet stretching the entire length of the Florida Keys from Key Largo to Key West.

In Florida, you can’t get farther than 100 miles from the ocean, and that doesn’t even consider any of the plethora of natural freshwater springs scattered around the state. And from snorkelers to experienced cave and technical divers, we have something for everyone.

So come on down, we’d love to have you. And bring the family- with plenty of zoos, museums, malls, and theme parks all around the state(there’s a mouse and some of his friends that are fairly popular with children who live around here) there is plenty to keep divers and non-divers alike of all ages happy.
——————-

Article Written by:

FloridaDiveTravel.com is owned and operated by Devon Grimmé, a dive instructor based in Gainesville, Florida. He has logged hundreds of dives in Florida waters, and knows the state like the back of his hand. Realizing that there was not a single place where divers could find reliable information and help for planning vacations here, he saw an opportunity to showcase his home state. Replicating the successful DiveConcierge.com model for international dive vacations, FloridaDiveTravel.com is the local expert for everything underwater in Florida. Visit our site, and visit our state!

The Ocean Awaits,

Devon

The boat turned the bow to the sea again and I was sitting on the sundeck thinking that I could have had use for more than a day in between the trips. I had left Marsa Alam around 1:30pm so arriving in Hurghada later the same evening there was no use in wasting time. Go directly to the Dive Pro’s local waterhole. There I got together with Henrik and a few other people in a desperate attempt to kind of socialize.

You definitely need to spend some time with people who are neither guests on your boat nor co-workers in between trips. I often think of the dive industry in general, and Hurghada in particular, as an “Upgrading Facility for Nuclear Family Waste”. Maybe it’s the only place where we, the people who does not fit into the norm of normal society can and find a space where we don’t have to be the outsiders, even be useful. For this to work there has to be others of the same kind to hang out with. The dive industry provides that, a world within the world, a society outside society that accepts the outcasts.

I knew that I’d have the chance to sleep in the morning so there was no panic to get to bed early. But you know how it is when you finally get a sleep in morning… I woke up at 7am and could not get back to sleep to save my life. I got up and since I had some stuff to do I got started right away.

Hisham (owner of the liveaboard boat) had called me the night before and told me that he’d be picking me up at 6pm so I calculated that we would be in Marsa Alam around 9pm. I then entered that information into the part of my brain that’s converting and adjusting to Egyptian reality and concluded that it was more likely to be: Picked up at 6:30pm and arrive in Marsa Alam around 9:30. At 9:30 we had not yet left Hurghada. That’s actually about the time Hisham decided that getting the car washed before getting out on a 3 hour drive through the dusty desert would be a good idea. Now we could finally get on our way into the arid region. Luckily I was alone in the back seat so I could stretch out and sleep.

As sure as last time was a track record this time was not. We stopped at every little village on our way to pick up this or leave that or to just stop for God knows what reason. Though I was still comfortably spread out in the rear I started to feel like I could have taken a taxi on my own just to be sleeping in my cabin on the boat already. Finally we drove into the port area around 2am. The guests were already vast asleep so without further postponement I hit the sack to get a few hours of rest.

So, there I’m sitting on the sundeck looking at the sea trying to figure out what to do about my sinus infection that keeps bugging me and make my ascends scrutinizing painful. I’ve made three dives on this first day of the safari whereof one being a night dive and I can not remember that I’ve ever been in such pain before. This including the time I broke my collarbone, the time I stepped on a nail and got my foot penetrated right through and the time I busted my eardrum during a stupid apnea attempt in Greece. It’s not only that I’m supposed to dive when I work. I also miss two out of three dives on Little Brother Island. This is annoying as it’s the dives I love the most in Egypt. Well… Gray reef sharks, Silky sharks and a Hammer head shark on the first, and for me only, dive has to count as a good day on any report…

Next day we dive Big Brother Island. There are two wrecks on the north tip of Big Brother; The Aïda and Numidia. Of course I’m still not fit for diving in the morning so I miss also the dive on Aïda. I do get in the water for the second dive. The wreck of Numidia but as my head is about to explode on the way up I decide that it has to be dry duty for me for the rest of the safari. When I get back to Hurghada I’ll get an appointment with a specialist doctor to get some proper treatment. This can’t go on. Bearing in mind that I’ll make the same trip the week after next and then next again and again, there’ll be plenty of opportunities for me to dive those sites then but it’s boring to sit on the boat waiting… On the same token; I’m used to accept and deal with boring situations, hence I take the opportunity to write this Status Report during those unwelcome breaks.

The weather conditions won’t allow us to go to Daedalus Reef. Instead we head towards Elphinstone for our forth day. Obviously we (the staff) know that the guests will be happy with the dives there since it’s an extraordinary dive site with corals in extremely good condition and sharks to meet any requirement. Although, as long as the dive magazines back in Europe keep writing about the diving in the deep south of the Egyptian Red Sea, people will come here with their minds set on a certain route whish they’ve red about. Then it might be hard to convince them that this is a better option. Still, if you’ve got the gift of making people believe that it’s actually their idea and their decision… then you’re home safe… Present and plant the right facts that can only lead to one suggestion and that’s the suggestion that’ll come up. Result: “Ok, so you’d rather go to Elphinstone? No problem! If that’s what you want, then that’s what you’ll get”. Badabim badaboom… Bob’s your auntie… Everybody’s happy!

I’ve already been up for a while when we moor up to Elphinstone around 6am. I’ve had my coffee, made the map for the briefing and knocked on the cabin doors to wake the guests up. Everybody is sitting on the upstairs sundeck and the sun is quickly mounting the slight overcast of the early morning. An Oceanic White Tipped Shark comes cruising around the boat, then one more, and another one. All three of them comes up close to the dive platform as to say “Good morning and welcome to Elphinstone. We’ll make sure you’ll have a pleasant dive.” And I know that I’m not going to get into the water because of a stupid sinus infection.

There are two kinds of people in the world: Those who can dive and those who can not dive. This doesn’t necessarily have anything to do with certification. One of our guests is Rafael. He belongs to the latter category. On land he’s as sweet as can be. In the water this guy is a nightmare! First of all he’s got absolutely no buoyancy control. He weighs around 110 kg (a wild but respectful guess) and measures around 170cm tall, the type of person that’s easier to climb over than to run around. He’s wearing 14 kg of led and a 3mm full suit. He can’t get off the surface but he can’t stay up. When he deflates his BCD (and finally stops fining up) he shoots to the bottom, back first, and crash-lands like JAS 39 Gripen, then he’s rolling around on the corals like caterpillar. When he finally finds his inflator he inflates and rockets back to the surface. All this he manages to do during the first few minutes of the check-dive the first day. Second dive is similar even though both I and Hisham had a talk with him and his buddy about weights, buoyancy and preserving the marine life. Result: Rafael is not diving, at least not on the walls where we don’t have bottom on a lifesaving depth. Most of the dive sites on this trip you end up on near to 1.000 meters if you persist to go all the way to the bottom. We take him for a dive a day; one-on-one-style on merely DSD-level just to give him the chance to see some of the Red Sea Wonders but it’s an ordeal bordering unfeasible proportions. Rafael is a CMAS*** diver with 160 dives under his belt. Knowing that, you don’t really expect any problems from him. Maybe with the exception that he might want to go a bit too deep.

However, Rafael is like a big Teddy bear, the nicest person you’re ever likely to meet and he’s totally ok with our decision not to let him dive the more challenging dives. I would like to meet the instructor who certified Rafael as a CMAS***, even as a CMAS* actually. I often hear from CMAS divers how PADI is an organisation that spews out crap divers that are dangerous for themselves and others. Well… Yeah… What ever… On top of all this Rafael managed to fall down the stairs on his way to his cabin, bang his head in a doorpost so bad that he almost passed out plus getting a stomach infection so bad the last day that we had to go back to shore before we had a chance to make the last dive to get him to the hospital. For a while I was convinced that unfortunate Rafael had boarded our boat to die. Well, he survived but I think it’s safe to say that this was not Rafael Cordoba Almela’s week.

Even when he wanted to buy some T-shirts as presents for his kids we didn’t have them in the right sizes… I almost started crying! One good thing happened to him during this eventful holiday. The topic of Champions League came up and different guests supporting different teams were debating which team was the best and all the usual football crap. Rafael was sitting silent and calm for a while and then he went to change his T-shirt… Coming back with “Real Madrid – 29 Victories” all over his impressing wide chest and a big smile all over his equally impressing wide face. The saloon went quiet. Then and there, Rafael was my hero.

All in all we’ve had a wonderful week and a rather dramatic last surface interval. When I get back to Hurghada I’ll go to a specialist doctor to get my sinuses taken out and replaced with brand spanking new oil-filled-titanium-computer-guided-artificial-ones…

O.A.O.
Samaka

Trelleborg products are found in a wide variety of contexts worldwide. They seal, damp and protect, both in everyday settings and under extreme conditions.

A Viking wearing a Viking: Robert Hedin, Commercial Diver

If, like my friend Rob, you are a commercial diver (or indeed a hazmat, military, fire & rescue or law-enforcement diver), then you will likely be intimately familiar with at least a couple of Trelleborg’s range of Viking Drysuits, as these are now the industry’s standard. They are impermeable, durable suits that can be used in a wide range of environmental conditions where there exist set standards for safety—they are extremely abrasion-resistant, will protect a diver from any contaminants in the water and can be easily washed down and decontaminated afterward.

If, on the other hand, you are simply diving for pleasure and not intending on exposing yourself to any toxic waste, you should still be aware of the existence of vulcanized rubber suits^*, particularly those with the Swedish Viking brand and specifically their old Sport and new ProVSN drysuits. The EPDM rubber of these suits is amazing stuff. If you cut one of the suits across its seam, you will see that there is actually no seam: the manufacturing process bonds the two separate layers so that they become one, which for you and I means… no leaks!

Viking Sport Drysuits

During the 1980′s Trelleborg introduced their Viking Sport drysuit, aimed at light technical and recreational divers. Although similar in appearance to their red and black commercial siblings, they are made from a lighter-weight rubber. These are no longer in production but can be purchased reasonably cheaply secondhand and, unlike crushed neoprene suits from the same era, will require little repair beyond new neck and wrist seals, if any, to get them back in action. Any repairs that you do need to make are as simple as patching the hole in the inner tube of your bike tire and can even be done hastily and temporarily in the field.

Viking ProVSN Drysuits

Towards the back end of 2009 Trelleborg released their new Viking ProVSN drysuit. I can’t say enough good things about these suits. The armatex nylon layers that sandwich the rubber central layer are stretchy and create a great-looking, comfortable suit that is available in front and back entry versions, with a variety of customisable features. Perhaps the only drawback of the suit is that the outer layer is permeable and so it is “problematic to decontaminate”—for most though, that is unlikely to be a problem.

What’s this about The Vulcans?

Vulcanization is a process best explained by someone else! So here is a link to a Google search: What the hell is vulcanized rubber?! The process makes rubber more durable and as far as a drysuits go this is great news; not only are vulcanized rubber suits incompressible (and so do not become less buoyant with depth) but they are also extremely hard wearing.

Who doesn’t like to see fellow human beings wearing rubber (or is that just me?)

First off this is the first step on the professional scuba courses and professionalism  is of paramount, so after paying my course fees!  it was a new drysuit neck seal,  new set of  regs, crew pack  so not an inconsiderable sum, but necessary to start on my journey.

Week one:  Friday the fifth, all day from 10.30am in the classroom with Chris my instructor and fellow Divemaster trainee Paul we went through every knowledge review that we had home studied the previous week into great detail, we were then thrown in at the deep end and asked to prepare a dive site map and present a dive briefing to four other instructors, a quick visit to the toilet and ten to 15 minutes later, calm had been restored and my legs had stopped shaking, but I had a sense of achievement and the de-brief was nothing but constructive and informative,

4:30pm  Student would be arriving soon for a pool session  so out of the classroom  and get everything prepared for the van to take the equipment to the pool  Phew !

Paul and I were briefed on what we would be doing and it was a skill circuit  of  every skill you have ever done and more  from Giant stride entry to controlled emergency swimming ascent, all done to demonstration quality and all marked on a scale of 1-5 with the onus put on improving all the time . One hour 16 minutes later were out of the water both my calves had cramped and were refusing to loosen , but no let up yet  de kit, put everything back onto the van  back to dive shop unload  and debrief .  I got home about 9:45pm exhausted   but let me tell you fully fulfilled in what we had all achieved in a long day.

So in summary  It was everything and more  I had hoped for  and I am looking forward to tomorrow 11/02/10  another long day  in the classroom this time Physics, Physiology and Equipment, Happy days,  next instalment soon.

Nick

OR

Adiabatic Compression, as it applies to scuba divers.

Why does my instructor get excited? What exactly is adiabatic compression and why do I need to know about it?

Your instructor gets excited because of the possibility of fire or explosion! Adiabatic compression is defined as a process where high-pressure gas flows at or near sonic velocity toward the low-pressure end of a piping system with a major restriction, such as a dead-end, a down sizing, or an abrupt turn. The likelihood of a reaction (ignition) increases with increases in the rate of gas compression and gas temperature.¹

So let us break that down into terms that are understandable and apply to scuba diving and let you the diver understand why it is important. We all use compressed gas, usually air, to scuba dive with. Some divers use enriched mixes called nitrox. This is a compressed gas with a higher concentration of oxygen than air or a PO2 greater than 21%. There are also divers who use 100% oxygen (O2).

As you know, when a gas expands (decompresses) it cools. When a gas is compressed, it heats (also known as heat of compression). In a closed system, scuba unit, filling bank, etc… you are allowing the gas to move from a compressed state to a expanded state then back to a compressed state. Most people have seen and felt this when their scuba cylinder is filled rapidly the sides heat up. This is compression of the gas. If you allow the gas to flow freely from the cylinder valve, it expands rapidly as the pressure reduces and there is a decrease in temperature at the valve. It can be so great as to have frost form on the valve. This is expansion of the gas.²

When compressed gas flows from high to low pressure, it can quickly reach a very high velocity, especially at constrictions, valve seats, regulator poppits and angular fittings. In these instances, flow velocities exceeding 148 feet / sec. (45 m / sec.) are considered to be dangerous. There is even greater danger when the speed of the gas flows at or near sonic velocity (speed of sound is approximately 1,125 feet per second at 68o F). When speeding gas strikes an obstruction, it is instantly recompressed and the ambient temperature instantly skyrockets because no heat is lost to the surrounding materials (instantly in this case is not instantaneous but rather very, very fast). The higher the initial pressure, the greater the temperature generated.³ High temperatues can cause auto-ignition of containment material.

With 2,000 psi oxygen (PO2 100%), temperatures well over I,500°F can be momentarily produced. This is sufficient to ignite even such inert substances as Teflon and stainless steel. To state it simply, an uncontrollable fire can ignite and burn, hoses, metal and YOU.

This phenomenon, similar to diesel ignition, is called ADIABATIC COMPRESSION. Great care must be taken to control adiabatic compression.

Scuba cylinders are frequently filled, pressurized and depressurized by the diver. The potential for danger exists with concentrations of oxygen greater than that found in air (PO2 21%) and incomplete understanding of Adiabatic Compression.

How do you prevent mishaps? With careful design and operation of gas flow and filling operations and specific education about gas pressurization and depressurization. Several O2 fires have occurred during the preparation of diving gas mixtures due to lack of understanding and a inappropriate attitude toward adiabatic compression. Mishaps include oxygen hose fires where Teflon-lined hoses with stainless steel over-braid have detonated and burned , throwing molten particles about. Other accidents have included the neck of a scuba cylinder being blasted open and launching the valve.⁴

To prevent accidental detonations, always open O2 cylinder valves very slowly and pressurize systemic components as “gently” as possible. Design your system using slow-opening globe or needle valves that contain seats made from oxygen-compatible polymers. Transfer oxygen gas slowly to prevent excessive heating. The maximum transfer rate for pure O2 is 200 psi / minute and rates during mixing are usually 50 – 70 psi / minute. And lastly, open your scuba cylinders slowly, gently pressurizing the system.

Charles law states: “For any gas at a constant pressure, the volume of the gas is directly proportional to its absolute temperature”⁵ or more simply put “when a gas is compressed, temperature is raised”.

So remember, when working with compressed gases, always open the valves slowly. Gently pressurize systems. Transfer pure oxygen at 200 psi per minute or slower. And if you are involved with mixing gases, do not exceed rates greater than 50 – 70 psi per minute.

It can save your life!

For more information on Adiabatic compression and gas mixing consider taking a Mixed Gas Blender or Oxygen Service Technician course.

Some additional definitions of Adiabatic compression.

Adiabatic compression is a process where there is not heat transfer to or from the system, and all supplied work is added to the internal energy of the gas, resulting in increases of temperature and pressure. Adiabatic compression or expansion is favored by good insulation, a large gas volume, or a short time scale (high power level). In practice there will always be a certain amount of heat flow, as to make a perfect adiabatic system would require perfect heat insulation of all parts of a machine.⁶

Adiabatic compression is a chemical or mechanical process in which there is no exchange of heat with the surroundings (no heat entering or leaving the system). It is applicable to enclosed systems.⁷ The relationship of pressure and volume when a gas or other fluid is compressed or expanded (with no loss or gain of heat) is that compression causes an increase in temperature and expansion a decrease in temperature.

¹ Neal, Jan and Morrissette, D.. (1998). Mixed Gas Blender And Oxygen Service Technician. p. 11. Daytona Beach, Florida: Underwater Dynamics, Inc.

² Taylor, Larry “Harris”, Ph.D. Adiabatic Expansion. A Gas Laws Primer. 9 Mar 2010. http://www-personal.umich.edu/~lpt/primer.htm .

³ Boyd, Richard, Dr. and Kent, Greg. Inherent Hazards Of Pressurized Oxygen. Engineering Nitrox Partial Pressure Blending Systems © 2002 . GMC Library. Global Mfg. Corporation. 9 Mar 2010. http://www.gmcscuba.com/pdf/engineering%20nitrox%20partial%20pressure%20blending%20systems.pdf .

⁴ Boyd, Richard, Dr. and Kent, Greg. Inherent Hazards Of Pressurized Oxygen. Engineering Nitrox Partial Pressure Blending Systems © 2002 . GMC Library. Global Mfg. Corporation. 9 Mar 2010. http://www.gmcscuba.com/pdf/engineering%20nitrox%20partial%20pressure%20blending%20systems.pdf .

⁵ Heine, John, Bookspan, J. and Oliver, P.. (2000). Diving Physics. NAUI Master Scuba Diver. p.89. United States of America: NAUI.

⁶ Adiabatic. Temperature. Gas Compressor. Wikipedia. 20 May 2007. http://en.wikipedia.org/wiki/Gas_compressor.

⁷ Adiabatic. Chemical Molecule Library- Glossary. 9 Mar 2010. http://www.ch.ic.ac.uk/vchemlib/mol/glossary/ .

Dive Safe!

Dean

I’ve been doing some traveling, had the fantastic opportunity to travel and dive from St. Thomas all the way up through to Miami. Dove some beautiful places that not many other people can claim to have dove – Cay Lobos for one (if you ever have the chance…GO!) and saw a huge range of species, lionfish included unfortunately, but only from Puerto Rico north (though I hear they’ve been sighted in the BVIs!). Another thing I noticed is pictured to the left. Which, as I said, made me pause.

Flamingo Tongues (Cyphoma gibbosum) are gorgeous, people can’t really argue with that. It’s pretty interesting how little we know about them. We know that they are a gastropod, or a snail of a sort; we have a good idea that they like to feed on soft corals like the gorgonian pictured above and the sea fan below; the spotted pattern you see is not the shell, but the soft mantle of the organism living in the shell; personally, I think that octopus like to snack on them as I often see the shells scattered about the openings of known octopus dens in Saba. Other than that I can find very little on what else eats them.

Technically speaking, flamingo tongues can be categorized as parasites, munching on soft corals and giving nothing in return, though not necessarily killing the entire colonial soft coral. But then again, it depends on your definition of the soft coral. If you see the soft coral as one organism unto itself, the flamingo tongue is a parasite. However, if you see the soft coral as a collection of individual tiny organisms called polyps (which it also is), then the flamingo tongue becomes a predator, killing its prey as it goes.

But that’s a debate for another time. My concern is the over-abundance of them on certain dive sites around the Caribbean. I first saw this kind of “infestation” in St. Eustatius (Statia), in the Netherlands Antilles – otherwise known the island next door to me. It was on a weekend dive trip last July (2009) and according to the dive shop it had just started a few months back. When we had visited the previous June (2008) we saw nothing like this at the exact same dive sites. I’m currently waiting on some photos for documentation and additional details.

Like I said, I spent 3 weeks diving over 1000 miles of ocean, USVIs, BVIs, Hogsty Reef, Turks and Caicos, all up the Bahamas, and no where did I see any of this – except Mona Island off Puerto Rico. From the what I’d heard from others who’d dove there more often than me, it was isolated to two dive sites (the names escape me – but 40-60 ft / 12-18m depth on the south side). These sites are where the posted pictures came from. And on doing some research, I’ve discovered they’re also having some concerns in Bonaire, enough that they’re asking divers to do volunteer surveys to track the problem.

According to an article posted on the CEII Research station in Bonaire, the problem may be traceable back to either a) loss of predators due to overfishing that caused a chain reaction and a decrease in predators OF flamingo tongues (doesn’t mention what those predators are…), or b) run off or otherwise addition of chemicals such as nitrogen and phosphorous which act as fuels for algae and “disease-bearing pathogens such as the fungus Aspergillosis sydowii” which has been known to cause Caribbean sea fan mortality. Why the flamingo tongues are more apt to predate on sick sea fans I’m not sure – its not likely that the sick sea fans are less likely to be able to run from the snails. More importantly, the flamingo tongues can also help spread the Aspergillosis.

My question to the diving world is: where else is this happening? Does anyone have any information on flamingo tongue predators? What do you know?