OBJECTIVES:
1.  Describe the types of organisms that are found in each or the four life zone.
2.  Explain four ways water density affects the diver.
3.  Describe 12 environmental factors that need to be considered when completing a site survey.
4.  Explain the purpose of an emergency plan.
5.  Describe the major problems associated with diving and explain the signs/symptoms and first aid treatment of each.
 
 The ocean is made up of four life zones, with each zone over lapping other zones while still retaining a uniqueness of organisms.  The littoral (intertidal) zone displays the harshest environment of the four life zones.  Creatures inhabiting this zone are subjected to both periods of being underwater and of being exposed to the sun and air.  The intertidal zone is that zone the is between high and low tide.  It is characterized by organisms that are adapted to living both under and above water.  Typical organisms that live in the intertidal zone include barnacles, sea anemones and critters caught in tide pools (small pockets of water that retain some of the critters of the intertidal zone).

 The benthic zone contains organisms that live on the bottom (as opposed to in the water column.  These organisms can be either sessile (attached to the bottom) or mobile (able to move freely) and can be either plants or animals, although most of the organisms are in fact animals.  One way of characterizing benthic organisms is by how they feed.  Filter feeders filter food from the water.  Caution should be taken when eating benthic organisms due to the concentration of pollutants in the tissues of these organisms through filtration.  Toxic products have a tendency to accumulate in a process called biomagnification.  Examples of benthic organisms include clams, crabs, corals and barnacles.

1.  What types of animals are typically found in tide pools?
2.  Name three other organisms that live in the benthic zone.

 The planktonic zone is characterized by organisms that float in the water, both plant and animal, and move only with the currents.  Zooplankton is the common name for the animals floating about, while phytoplankton is the common name for the plants floating about.  The nektonic zone includes those animals in the water column that have the ability to swim.  Scyphozoans (true jelly fish) are considered to be nekton because they have the ability to move about freely.  The Portuguese Man of War (not a true jelly fish, but a hydroid instead), is considered to be planktonic due to its inability to move freely.  Both Scyphozoans and the Man of War contain stinging structures called nematocysts, which is why they are often mistaken for the same or similar organisms.

3.  Why do jelly fish and hydroids pose such a big problem to divers?
4.  Name three other organisms that live in the nektonic zone.

 People/divers entering into any of the zones listed here should be mindful of environmental issues and preservation.  At present the ocean seems to be an infinite resource; however, over fishing, improper disposal of waste products and the lack of careful planning will quickly turn this vast resource into an underwater desert waste land.  Things to consider when collecting from the ocean include the consideration of where the organisms came from, how will removing it effect the area I’m visiting, and why  do I need to remove it.  Live organisms like coral and shells seldom survive outside of their original habitat.  Consider leaving them for others to enjoy.  Taking fish for food purposes is fine, but spear fishing should take place in areas restricted for spear fishing, and fish should never be taken for the purpose of killing fish.  By setting positive examples for those around us, we can have a positive impact on the environment and retain the underwater beauty for years to come.

5.  Think of the attitude, “This is only one shell or one critter.”  What impact could this statement   have on the environment?

 Recall from your basic scuba class the properties of water as compared to air.  If you remember correctly water is 80 times more dense than air.  This density difference effects light, sound, heat and propulsion. 

6.  Give two ways that light is effected by the density of water.
7.  How much faster does sound travel underwater, as compared to air?
8.  What is the main consideration with regards to the heat capacity and transfer of water?
9.  How is propulsion of a diver effected by the density of water?

 In answering the above four questions it is important to realize that as the density of an object or liquid increases, so does the closeness of the molecules.  This “thicker” medium allows objects and energy passing through it to act differently than if the molecules were farther apart.  For this reason, light energy is slowed down in water and light is refracted or bent.  Also, as light energy is slowed down, colors are absorbed by the water in order of the color spectrum (red first, orange second, yellow third, with blue being absorbed at the end).  Even in crystal clear Caribbean waters fish and other normally colorful marine animals appear dull and colorless, at least until artificial light is added.  Sound, however, has the opposite effect in water.  Because water molecules are closer together, sound waves can “bump” the molecules together more quickly.  This leads to sound traveling almost four times faster underwater.  The diver is effected by this change because sound becomes omni directional and a diver has a difficult time determining which direction the sound is coming from. 

 Heat capacity and heat transfer are two very important considerations in diving.  If you think about the air around you, it’s not unusual to go outside and work in the yard or even sun bathe when the temperature is 75º F.  Unfortunately, swimming or scuba diving in the water at the same temperature is an entirely different story.  The reason for the difference is once again a product of the differences in density.  Because air molecules are farther apart (less dense) heat is not taken from our bodies at the same rate as in water (more dense, particles are closer together).  In fact, water conducts heat 25 times faster than air does.  This difference means that hypothermia can quickly set in when scuba diving in cool water.  To avoid any problems an exposure suit should be worn any time temperatures are below 85º F and diving exposure extends for a long period of time.

 By this point I’m sure that you can figure out how density of water will effect the propulsion of a diver.  Even with limited experience, most people quickly realize that it is harder to move in water than it is in air.  For this reason streamlining yourself and your equipment is extremely important, as is wearing properly fitting fins.  Streamlining your equipment is a simple matter of connecting those loosely hanging hoses such as your gauges and octopus to your BCD, while streamlining your body is a bit more complicated.  To streamline your body, start by pulling your arms in to your side (try crossing them or holding your hands at hip level). then get your head down.  One of the biggest problem with new divers is that they tend to swim head up.  Think of putting your head down so that you can get a closer look at what’s on the bottom.  If you swim in a head down position, you will reduce your frontal drag and save more energy, which in turn, decreases your air consumption and gives you more bottom time.  The total effect is that you will be more comfortable in the water, you will be able to stay down longer, and you will be less fatigued when you are finished. 

10.  What are the four ways that water density effects a diver? 
11.  You are diving at 50 feet and find a piece of the U.S. flag that includes both stars and stripes.  You reach to pick it up to take a closer look.  Write down four observations about your experience in completing this task.  (Hint:  How do the four effects of density fit into what you are writing?)

DIVE PLANNING
Proper dive planning is essential for increasing safety and enjoyment.  A thorough dive plan includes an evaluation of the environmental conditions, an emergency plan of action, planning your diving activities, and doing a complete equipment check.  The acronym that we use to cover all of these areas is S.E.A.B.A.G. 

 Site survey is a complete evaluation of the dive site.  Using the acronym T.V.N.E.W.S.M.E.N. will thoroughly cover all of the environmental factors that may be encountered during the dive.  Tides and currents are evaluated by observing both the surface movement of the water and any area tide charts available.  Recognizing the conditions that produce water movement is crucial.  Winds (which produce waves) coming in towards the shore at an angle produce “long shore currents” that run parallel to shore in the direction that is adjacent to the direction the wind is blowing.  Remember that waves produce energy and that that energy is carried through the water column towards the bottom (the stronger the wind the bigger the waves).  Divers feel this energy as surge and the greater the energy the greater the surge when diving.  Wave height and wave length (the distance between two wave crests) are important factors to consider when determining how much energy is being produced.  Plunging breakers, those that continue to build and then crash abruptly at the shore, produce the greatest force and should be given the most respect by divers.  Rip currents are another important consideration.  Most rip currents can be observed from shore by looking for muddy, brown water that is characteristic of water with a large amount of energy.  Rip currents are caused by large amounts of water being forced through narrow channels, creating strong currents.  Life guards often post rip current warnings in areas of strong rip currents (if ever trapped in a rip current, swim parallel to shore until you are free of the current).  Tides are caused by the gravitational pull of the sun and moon (mostly the moon) and produce currents that travel in the same direction of the tidal water movement.  Higher the tidal changes (spring tides) typically produce stronger currents, while lower tidal changes (neap tides) typically produce weaker currents.  Remember too that tidal changes can effect depth and visibility.  You should always consult a tide chart before diving and always plan your dive into the current first.  The return home will be much easier.  (Just as a side note:  Lakes too can produce waves caused by seiching, which is the rocking back and forth of water caused by the sun, moon and the spin of the earth.) 

 Visibility is affected by the movement of these water, as well as aquatic plant life (especially during aquatic blooms, such as red tide).  Looking at the water prior to entering can provide clues as to the amount of visibility present.  Brown, mucky water is characteristic of poor visibility, while blue and light green waters that appear clear are characteristic of good visibility.  The next thing to consider are 

 Natural hazards.  Natural hazards can best be found by contacting a local dive professional and/or talking to someone who frequents the area.  Knowing about natural hazards prior to entering the water can prevent unnecessary stress and anxiety during the dive, increasing your comfort level.  Marine life hazards can be categorized into five categories:  Stingers, like jelly fish and hydroids; Stickers, such as sea urchins, sting rays and rock fish; Scrapers, like barnacles and coral; Snappers, such as eels, sharks and sea lions; and Shockers, like electric rays and electric eels.  (Potential treats for fresh water divers include:  alligator snapping turtles and water moccasins.)  First aid treatments for injuries from these critters should be reviewed prior to each dive, and every diver should have a personal, dive specific first aid kit. 

 Having a primary and secondary Exit point is also important to plan for in case conditions or circumstances change during the dive.  Planning your exits at this point will allow you to consider the terrestrial aspects of the exit, as well as the water aspects. 

 Weather conditions should be taken into consideration, as well when planning your dive.  In some areas of the U.S. (i.e. desert Southwest), storms can appear from out of no where and change the conditions under which you are diving.  Weather conditions may also effect what you wear as a dive Suit.  When suiting up, it is important to compare water temperatures with water temperatures of previous dives and known temperature ratings of suits.  Thermoclines are likely to be present in waters that don’t receive a lot of water movement, like lakes, but could also be present at depth on ocean dives.  (Lakes will have a more even temperature range in the spring, during times of high runoff, but visibility will be much poorer during these times.) 

 Another consideration in the site survey is that of Man made hazards.  In many areas boats will be the most problematic man made hazard.  Careful consideration should be given to the boat traffic of the area you are diving.  Before entering the water, you should look for both primary and secondary Entry points.  A secondary entry point may be necessary should your primary entry point not be accessible at the last minute due to condition or circumstance changes. 

 The final area of consideration for a site survey is that of the Never do’s.  Every area has something that you should never do at that dive site (i.e. never swim past the point because of strong currents, never get too close to sea lions when they have pups, etc.).  Again, the best place to find out about the never do’s is to contact a local dive professional or someone who frequents the area you are diving. 

12.  What is the importance of the site survey?
13.  How can a properly prepared site survey help prevent diving problems?

 Emergency plans is the next step in SEABAG and should be made prior to entering the water.  It is important that you discuss with your buddy(ies) what to do in case there is an emergency.  Some of the items that should be considered when making your emergency plans are:  where is the nearest phone and who are you going to call, does the phone work?  Where is the oxygen and first aid?   Who is qualified and knows how to administer both?  What is your lost buddy plan?  How are you going to know if your buddy(ies) is/are in trouble?  Planning for an emergency will make dealing with an emergency much easier should one occur.

14.  What are the emergency numbers for the dive sites that you frequent?
15.  What are you going to tell them when they answer the phone?

 Activities.  Your final pre dive, pre gear-up task is to determine what you are going to be doing in the water.  At a minimum you should determine your limits:  What is your time limit?  What is your minimum air limit?  What is your maximum depth limit?  Who is going to lead the dive.  What, if any, are the special signals that need to be used during the dive?  Remember the adage, “plan your dive, and dive your plan.”  If everyone in your party knows your limits, then everyone knows what can be expected during the dive.  Other considerations for dive planning include additional activities.  In order to determine these activities everyone diving should take into consideration their personal limitations, such as emotional condition, health and fitness, experience, equipment and the environmental conditions of the area being dived.  After determining everyone’s person attitude, then you should ask what are we going to do?  Will you be taking pictures, spear fishing, completing required training dives?  Answers to these questions can help to determine the progression of the dive and the amount of area to be covered. 

16.  Starting as a “C” diver what is the Adjusted Maximum Dive Time for a dive to 60 feet?
17.  If I completed the above dive and dove for a total of 25 minutes, what is the end of the dive letter group?

 After completing the SEA portion of SEABAG and then gearing up, you will complete the pre dive equipment check using BAG.  Buoyancy is checked by making sure that you and your buddy both have the proper amount of weight and that your BCDs are functional.  Inflate and deflate each others BCDs and determine how the inflator mechanisms operate.  Air can be checked by breathing into your own regulator(s) and having your buddy inspect the submersible pressure gauge at the same time (the needle should not move while breathing through the regulator).  This is also a good time to go through your out of air options.  These options include:  1) controlled emergency swimming ascent (shallow water), 2) octopus breathing and ascent, or redundant air supply, 3) buddy breathe (if an alternate air source is not available), and 4) (and definitely your last option) an emergency buoyant ascent (this should only be done if you know or feel as though you will be unconscious by the time you get to the surface).  Lastly, you and your dive buddy(ies) should grab your Gear (mask, fins, and snorkel) and Go dive.  By this time you should be thoroughly prepared for the task at hand.  Enjoy your dive.

18.  What is the importance of checking your buddy’s equipment?
19.  Why is it important that you know how your buddy’s equipment works?
20.  What factors should be considered when choosing an out of air option?

 Even though you have completed a thorough dive plan and followed the above recommended outline, that does not guarantee that problems will not occur.  Several dive related conditions can occur and are discussed here.
 Drowning is death caused by the aspiration of fluids into the lungs.  Near Drowning (breathing or aspirating fluids into the lungs) is the survival of at least 24 hours after suffocation by submersion in a liquid.  Someone who has suffered a near drowning can still die from what is known as secondary drowning.  Secondary drowning is the resuffocation due to the build up of fluids in the lungs after near drowning.  This is your bodies natural “defense” for having had fluids in your lungs.  Persons suffering from near drowning should be monitored by a physician at a medical institution.
 Other types of respiratory distress, their cause, signs/symptoms and first aid/preventative activities are listed in the table below: 
 

   The types of circulation distress, their cause, signs/symptoms and first aid/preventative activities are listed in the table below:
 

   The types of barotrauma, their cause, signs/symptoms and first aid/preventative activities are listed in the table below:
 

   The types of thermal considerations, their cause, signs/symptoms and first aid/preventative activities are listed in the table below:
 

21.  What are the two most serious pressure related problems not listed in any of the above tables?
22.  How are the problems listed in question 21 caused?

   The two most serious pressure related problems are decompression sickness (DCS) and arterial gas embolism (AGE).  Recall that DCS is caused from a build up of nitrogen in your body during diving and then your bodies inability to slowly release the nitrogen when the pressure decreases upon surfacing.  High quantities of nitrogen or rapid reduction in pressure causes the nitrogen to come out of solution and causes the formation of bubbles in the blood stream and in soft tissues.  Arterial gas embolism, on the other hand is an over pressure injury of your lungs and is caused by ascending while having air trapped, either forcefully or accidentally, in your lungs.  This air expands as you ascent causing a rupture of alveoli.  Air is then leaked into your blood stream or into the the chest cavity, or both.  Treatment for both DCS and AGE are identicle.  Note from the table below the main difference between DCS and AGE is in the time for the onset of symptoms.
 
 

If required decompression is missed, the diver(s) should remain out of the water, rest, take 100% oxygen, fluids and monitor for signs of DCS.  It is recommended that you discontinue diving for at least 12 hours.  If recompression treatment is needed, the procedure should consist of a 6 atmosphere treatment in a multi place, double lock chamber under the care of a physician with proper medical and hyperbaric training. 

23.  Signs and symptoms for DCS and AGE can be very similar.  Without medical evaluation, how can a dive buddy determine which condition is more likely to have occurred?

24.  That night at dinner, your buddy begins complaining about aches and pains in his arm and shoulder.  What condition from above would you expect?

25.  What should you do to help your buddy recover from the problem described in question 24?