What to teach: Reflections from another year of SCUBA instruction

Teaching SCUBA can be challenging for many reasons. People come to SCUBA diving for adventure, for healing, or for nature, and are often quelled from their pursuit by their own bodies and minds. As a SCUBA instructor, I try to help students get past mental anxieties, physical impairments and scheduling conflicts.  But the most challenging aspect is  teaching to instill a sense of wonder and respect for the sea, regardless of why a person came to SCUBA.

happy students, happy merbabe.

happy students, happy merbabe.

I became a SCUBA instructor because I love diving, I love spending time with divers, and I love to show people the ocean that I love. There’s a lot of love in that sentence, and because its something that I feel so strongly about, it doesn’t always feel like work. As a diver, the time I spend in the ocean makes me a better person, and makes me appreciate the planet I live on. Because this is why I dive, this is the lesson I want to pass on to my students.

 “The more clearly we can focus our attention on the wonders and realities of the universe about us, the less taste we shall have for destruction.”-Rachel Carson

My job is keep you safe, to teach you to never hold your breath, and to understand  the physics of pressure changes.  But it is also my job to show you what I love, incite your excitement, and to pass on the torch to protect the very thing that keeps us alive and breathing.

Teaching, learning, teaching.

Teaching, learning, teaching.

Here’s to another year of teaching, unheard cheerleading through my regulator, and seeing the spark of passion through masks underwater,


One more important quote from Rachel Carson.  If I, and others who feel the same, can’t incite people to adore the ocean;

“It is a curious situation that the sea, from which life first arose should now be threatened by the activities of one form of that life. But the sea, though changed in a sinister way, will continue to exist; the threat is rather to life itself.”

How jellies heal themselves

When you cut your finger, you (hopefully!) develop a scab.

When a sea star loses an arm, he grows it back!

So what happens when a moon jelly loses a limb, or is cut in half?

Moon Jelly!

Moon Jelly!

Scientists hypothesized that the jellies would also grow back missing arms, but instead something very interesting happened.

Moon jellies bodies rearranged themselves to become symmetrical again. So if they lost 4 of their 8 arms, the remaining four would spread out to become the most efficient.

Further experiments found that no matter how many limbs went missing, a jelly would make itself symmetrical again.

Death before asymmetry!

Death before asymmetry!

These jellies were healing themselves by swimming! As they pulsed through the water in search of food, the contraction and release of the muscles forced the limbs back into symmetry.  Why? Moon jellies must be absolutely symmetrical in order to survive.

Although jellies do have methods of moving through the water and of righting themselves if they are upside down, they are often at the whim of the currents of the sea.  This means that being radially asymmetrical is a huge liability and can prevent proper movement and feeding.

Check this cool video of a moon jelly utilizing his perfect symmetry to deftly capture his tasty morsels.

So, in an extremely efficient way, they save their existence by using what they’ve got. Could be a good lesson for us all, I suppose.




check the original article for original source

The color that you sea

Why is it that some places the color of the ocean is dark blue, and some places it is aquamarine? Why does the color change?


the blue water of California on a sunny day.

Like all visual perception of color, the answer has a lot to do with light and wavelength, and their absorption.

the visible spectrum

the visible spectrum

White light is made up of all the colors of the rainbow, and the perceived color of an object is the wavelength of color that is not absorbed the most.  So for instance, the ocean water Loves to absorb the color red.  The white light of the sun shines down on the ocean, and the wavelengths of color are divided by how quickly the are absorbed. Red goes first, and then orange, and then yellow, and so on.  But the ocean is very weak at absorbing blue color, so most of the water you see appears blue.

So, why is the water in Belize aqua and the water in California navy?

The answer has a lot to do with the fact that we are not looking at pure water, but at water that has particles in it.

California has a LOT of upwelling, which brings sediment and nutrients toward the surface from deep ocean basins. Those sediments in the water help to reflect and scatter the blue color, giving this part of the ocean a darker color.  It also provides the ocean with a lot of nutrients, allowing for algae like kelp to thrive.

But phytoplankton!



You all know, and love phytoplankton. I know I do.  Phytoplankton use chlorophyll for photosynthesis.  This is the basis of LIFE (carbon), which is why I just went ahead and assumed that you and phytoplankton were (K I S S I N G).

But seriously, chlorophyll has a green pigment, which makes phytoplankton especially good at absorbing blue and red wavelengths, and reflecting that green color back out again.  California has a lot of this science K I S S I N G happening (fine, photosynthesis), and this makes the water turbid (cloudy, opaque, not good viz).

Caye Caulker, Belize, aerial view

Caye Caulker, Belize, aerial view

The light aqua blue colors surrounding many shallow and young islands has to do with the nutrient lacking water (nutrients lacking from the water, therefore less color scattering) and the white sand on the bottom being heavier and less likely to remain stirred up.  The light penetrates deeper with less obstacles, the color is not as scattered, and there isn’t as much nutrient action making the water turbid.

any questions?

what’s your favorite color of sea?


How does a sea jelly sting?

Have you ever been stung by a jellyfish? Have you ever touched a moon jelly and wondered why you weren’t stung? Do you wonder why turtles can eat jellyfish (with their MOUTHS?)

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Jellyfish have tentacles that drift underneath from their bell that are covered in thousands and thousands of cnidoblasts.  Cnidoblasts have nematocysts with a coiled thread in them, that are triggered by a tiny follicle on the outside.

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Once an object comes into contact with the tentacle, the follicle  triggers the nematocyst to uncoil a thread and send out a stinging venom. Imagine a garden hose coiled suddenly filling with water and straightening out…that’s what a jellyfish sting is, except times a thousand!

Members of cnidaria have nematocysts (also corals and anemones), but they have varying degrees of toxicity.  The stronger the venom, the worse the sting feels.  Something like a moon jelly has a very mild sting, so most people don’t notice any reaction when touching a one in a touch tank, or at most a very mild reaction. Whereas the box jellyfish is so poisonous, its sting can kill humans in minutes.

jelly 2

a gorgeous jelly drifting, compliments of Dudley McLaughlin

Sea turtles and other animals eat live jellyfish drifting in the sea.  They are also stung as they eat them as well, but like humans with moon jellies, have tough skin and don’t notice or aren’t bothered by the reaction.

These poisonous stings work for self defense and for self preservation: all food that drifts into contact with the tentacles gets stunned and then brought up to the jellyfish stomach for digestion (in the bell!)

ring a ding, this bell has made impact.  Compliments of Dudley McLaughlin

ring a ding, this bell has made impact. Compliments of Dudley McLaughlin

Jellyfish are 95% water.  But they are amazingly interesting! Have you ever experienced the amazing unfurling of jellyfish nematocysts? Ouch!

Learn more about sea jellies this summer at the Aquarium of the Pacific, Summer of Jellies!

A jelly, hunting. Compliments of Dudley McLaughlin

A jelly, hunting. Compliments of Dudley McLaughlin

pb&jelly time,


Earthday 2015

Happy Earth Day 2015!

Our Blue Planet

Our Blue Planet

As you know, I choose to devote this blog to the more than 70% of the earth that is covered in Ocean.  “Earth” is kind of a misnomer…we are an OCEAN planet for sure!

But keeping in  the happy spirit of celebrating this beautiful planet that we call home, I thought I’d list  some of the best ways to appreciate  Earth.

Photo Credit to Dudley McLaughlin

Photo Credit to Dudley McLaughlin

1) See it.  Enjoy it! Go hiking, scuba diving, go for an after dinner stroll around the block.  Earth is a beautiful place, get an eyeful.

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2) Be a good steward: Pick up the trash you see.  Don’t litter.  Set a good example.  Don’t throw trash out your car window (including cigarette butts).  Don’t touch or capture wildlife.

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3) learn about earth.  Do you live in the desert? A wetland? the mountains? a rainforest? Do you know? Try to live as in sync with your part of the earth as possible.  For instance, Southern California is going through a drought right now.  We live in the desert.  So maybe don’t plant grass, or any plants that require extra watering.  You’ll be happier, and your part of the earth will be too.

Our Story - 095-2

There are small ways to make every day Earth Day, what will you do?


PS I am currently celebrating another year of teaching! Happy Instructor anniversary to my fellow PADI OWSI Class. :)

Scuba Instructors in Training...back in the day.

Scuba Instructors in Training…back in the day.

Ocean Vocab: Microbeads

What are microbeads?

Microbeads are tiny plastic bits that are in beauty and cleaning products.  They are valued for their abrasive properties (for instance, exfoliating face washes).  But they are so small, that we are incapable of filtering them out of water and they are making it into the ocean.

Once in the ocean, they are being digested by the bottom of the food chain and then working their way up, until they reach people again: in the form of the fish we are eating.

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Microbeads look like food to sea creatures, but are not as easily digestible.  Even if the animal is able to pass the microbeads through their system, what remains behind is like poison.  Plastic absorbs pollutants like pesticides, PCB’s, and motor oil.  In a test with mussels,  once the plastic microbeads had passed through the mussel,  the pollution remained behind for longer than the study lasted.

So to avoid getting them into our ocean, we have to avoid using them altogether, which means being conscience consumers, as microbeads are still legal and quite pervasive.  (Just as the use of DDT as a pesticide was, and ozone eating Chlorofluorocarbons were until finally outlawed)

Some products and brands with microbeads:

Aveeno, Bliss, Clinque. Kiehl’s, Neutrogena, Oil of Olay & Crest

(look at the full list here)

If you check the ingredients of your products and see:  Polyethylene (PE), look out. Polyethylene is a plastic that is not easily biodegradable, and is commonly what microbeads are comprised of.

Instead, look to brands like :Biore, Lush, St. Ives, & Aquafresh

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Or, if you’re looking for an alternative, cheap product, try baking soda.  Which works as a great exfoliant for your skin, can help scrub pots and pans, works on teeth, and is non toxic to our ocean.

Remember, if a product is advertised as an exfoliant or with “beads” of some kind, there’s a good chance it’s a microbead and you should reconsider.

happy weekend! use less plastic!


Light in the Ocean, But Only So Deep

Life on earth depends on the sun, and the light and heat that emanates from it. It is the base of photosynthesis. But light works differently underwater than it does on land.

Water is 800x denser than air, and absorbs light at a much faster rate.  As such, light and therefore color are less available underwater. The ocean is  classified into different levels depending on light’s ability to penetrate.

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The first zone is called the euphotic zone, which is right near the surface.  It is also called the epipelagic zone, or the well-lit zone.  The depth of this zone varies, depending on clarity of water (which can be distressed by turbidity, waves, wind, the make of the bottom). In some areas this zone is very shallow, and in some clear water areas it can be 200 meters deep.



Here is where photosynthesis in the ocean occurs, and is the bottom of the food chain. The side effect of photosynthesis is of course, the production of oxygen, meaning that this zone in the ocean is responsible for creating every second breath of air that  humans breath on land.

The next level is called the mesopelagic zone.  It is from about 200 meters to 1000 meters. Sunlight is less able to penetrate here, but it is not impossible. Light decreases as depth increases, and bioluminescence is visible.  Animals that live here learn to survive less on sight and more on feel. Many animals dive to this great depth to feed, including sperm whales.

The second deepest diving mammal, the Sperm Whale

The second deepest diving mammal, the Sperm Whale

Deeper  down are the  midnight zones.  No sunlight is able to penetrate this depth and it is absolutely dark below 1000 meters. Some people consider this area three different zones (Bathypelagic, Abyssopelagic, and Hadalpelagic-which I love because it is derivative of Hades, the ancient Greek god of the underworld, so fitting).  


Hades, Ancient Greek God of the underworld, with his canine companion Cerberus (who incidentally has three heads).


Because light cannot penetrate here, photosynthesis is impossible, and some may think this area is a wasteland,  considering that light is life. Far from it; this area has important work to do.  All of the waste and death that occurs toward the surface of the ocean sinks to the bottom and must be decomposed.  Amazing new explorations have shown us that animals at this depth even travel to shallower depths to feed on animals in the mid channel.

More than 3 quarters of the ocean is at this great depth, and very little is known about it.  It is difficult to get to, it is hard to see. But the same arguments can be made for space. As Dr  Robert D. Ballard explained it: “We played golf on the moon before we went to the mid-Atlantic ridge, which is the single largest geological feature of our own planet; we have better maps of Mars than of some parts of our own ocean floor.”

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As of this moment, 12 astronauts have walked on the moon, while only three have been to the depths of the Mariana trench’s Hadalpelagic Zone.  What else can we learn about the places of earth and ocean where light can’t reach?


“If at every instant we may perish, so at every instant we may be saved.”-Jules Verne, Journey to the Center of the Earth

What does an acidified ocean mean?

How does the acidification of the ocean change things? Increased carbon in the water may be a good thing for plants that use photosynthesis for food, like trees on land, but as acidity rises, the conditions become more corrosive to calcified organisms. The increased acidity reduces the availability of carbonate ions that shelled animals need to build their shells and skeletons. Here’s how that sucks:

Coral, not bleached by acid.

Coral, not bleached by acid.

Coral is both plant and animal; a polyp that grows it’s own exoskeleton, and it  is dramatically affected by the ocean’s increased acidity.  Acidification of the ocean reduces coral’s ability to grow, and even deteriorates existing coral.

Large areas of the world rely upon the coral ecosystem. Coral reefs are called the rainforest of the ocean: 25% of the world’s marine species live in and upon coral, even though they occupy less than 1% of the ocean. Tropical waters that are home to many coral ecosystems are actually very nutrient poor, and coral reefs provide the food and shelter that living things need to survive. The whole structure is dependent upon the coral’s presence.

Ocean acidification is eating away an entire ecosystem.

A pteropod: the butterfly of the sea.

A pteropod: the butterfly of the sea.

Pteropods are another calcified organism. You may not have heard of pteropods before because they can be very small, but they play a substantial role in the food chain. If pteropods aren’t able to build their shells, everyone further up on the food chain (including, salmon, penguins, polar bears) will end up hungry.   Humans, you may be aware, are also at the top of the food chain, and  already benefit greatly from tiny pteropoda when most of our farmed fish and wild caught fish eat them.  Without them, we’re simply out of luck.

Sea urchin.

Sea urchin.

Sea urchins, clams, sea stars and mussels are other calcified organisms that suffer in acidic conditions. I could go into the detail about how each thing lost would create a ripple of devastation but there’s not really any more time to waste.

I don’t want to end this blog post on a negative note, but carbon is still increasing rapidly in our atmosphere and we’re not doing much to prevent that. Our oceans are absorbing more carbon everywhere the air touches the sea, and some scientists question if the ocean will ever reach a saturation point or if it will continue to carry our heavy carbon burden.

What are some ways to help? More next time.


PS: Here’s an interesting comparison.  The blood in human bodies has an average pH of 7.4 (ish).  If it drops below 7.35, the body’s ability to function is severely diminished.  If left unchecked, it can lead to coma, and death.  Now compare with what’s happening to our oceans… basically, we’d be dead already.

Ocean Acidification Simplified

I know you’ve heard the term ocean acidification, but do you know what that phrase means?


Noting a sharp increase of carbon dioxide since the Industrial Revolution.


Humans burn fossil fuels.  You probably burned some today on your way to work.  Fossil fuels burned add carbon dioxide into the atmosphere. We also cut down trees (deforestation) and when we do that, we lose our natural CO2 absorbers.  Annually, humans put in about nine billion tons of carbon into the atmosphere. This is an unprecedented level and it’s occurring because of man made, not natural reasons.

Mostly water here.

Mostly water here.


“Ocean covers seventy percent of the earth’s surface, and everywhere that water and air come into contact there’s an exchange.  Gases from the atmosphere  get absorbed by the ocean and gases dissolved in the ocean are released into the atmosphere.  When the two are in equilibrium, roughly the same quantities are being dissolved as being released.  Change the atmosphere’s composition, as we have done, and the exchange becomes lopsided: more carbon dioxide enters the water than comes back out.  … Every day, every American in effect pumps seven pounds of carbon into the sea.” (Kolbert, pg: 114).

Scuba divers may recognize Henry’s law in play in the paragraph above. 

Change in pH levels from 1700-1990's.

Change in pH levels from 1700-1990’s.

This changes the pH* of the ocean. 7 is neutral, above 7 is base, and below 7 is acid.  The current average was 8.2, and is now 8.1.   That number is lowered due to the increased absorption of carbon dioxide, which means the ocean is more acidic than previously.  You can see in the picture above that  pH levels have dropped all over the world since the 1700’s.

pH Scale

OK, so the burning of fossil fuels makes the ocean more acidic. Why is that bad?

next time… on the merbabe adventures.


The quote above is from The Sixth Extinction, by Elizabeth Kolbert.  This book reviews the 5 major mass extinctions of the history of the world, and makes the argument that humans are facilitating the 6th mass extinction presently. I highly recommend it.

*what is pH? :” pH (potential of hydrogen) is a measure of the acidity or alkalinity of a solution. It is measured on a scale of 0 to 14—the lower the pH the more acidic the solution, the higher the pH the more alkaline (or base) the solution. When a solution is neither acid nor alkaline it has a pH of 7 which is neutral.”


Sharks and Technology: How science is giving sharks a new chance.

It’s long been known that a species that has survived for millions of years is very suddenly approaching extinction levels.

A zebra shark at the aquarium of the pacific

A zebra shark at the aquarium of the pacific

Due to over fishing, pollution, and habitat loss, sharks are becoming ocean ghosts, which is leading towards a massive imbalance in our ocean ecosystem.

While conservation and ocean preservation is best, sharp minds haven’t given up on other options.  Just recently, the Aquarium of the Pacific (one of my favorite places) has been successful with artificial insemination with Zebra Sharks.

What does this mean? Well, it opens a lot of options for shark reproduction. It means Shark DNA can be shared over the country and the world, to increase genetic diversity in captive populations.  It means, maybe we can increase wild releases of captive born sharks to the ocean if needed.  It means, someone found something to do instead of just asking everyone to please stop killing the sharks and the ocean PLZ THANKS.

Merbabe diving with leopard sharks at the Aquarium of the Pacific.

Merbabe diving with leopard sharks at the Aquarium of the Pacific.

Two juvenile zebra sharks are being moved onto exhibit this week at the Aquarium, the product of the successful artificial insemination.  The public will be able to admire and even gently caress them in touch tanks at Shark Lagoon by Valentine’s day this year.

This is a picture of a whale shark in Utila, Honduras. Baby steps like helping captive sharks with artificial insemination could leave to the future preservation of sharks who give live birth, like this whale shark.

This is a picture of a whale shark in Utila, Honduras. Baby steps like helping captive sharks with artificial insemination could lead to the future preservation of sharks who give live birth, like this whale shark.

Although Zebra Sharks are born from eggs,  Aquarists are now working toward black tip reef shark artificial insemination, who have live births.  Baby steps could leave to giant strides in shark populations.

Thanks for the hard work, AOP. You do you.