Bioluminescense

Puerto Rico's bioluminescent bay

My wife's parents returned just yesterday from Puerto Rico. They report that in spite of my mother-in-law's fears of water and being in a boat, that one of their favorite experiences on this island paradise was kayaking out into the ocean and observing Puerto Rico's famous glowing water; created by many millions of micro-organisms called dinoflagellates that give off light, especially when agitated.
On our night dives in The Keys, we have a similar experience where part way through our after-dark dive, we have everyone turn off our underwater lights and then swoosh our arms in the water and see a fluorescent glow trail left by our arms. According to Isaac Bartholomew who has seen both Puerto Rico's glow and the one we see in The Keys, Puerto Rico's is much brighter but it is still a very cool thing to see at night in Florida.
Bioluminescense is a fascinating phenomenon. The word comes from the Greek bios which means "living", and the Latin lumen which means "light". So anything that is both alive and capable of producing light from it's life is said to possess bioluminescence.

firefly or lightening bug

jack-o-lantern mushroom

Though relatively rare, there are a wide variety of organisms that produce light. Here in Ohio we have our wonderful fireflies or lightening bugs. I have seen their larva, called glowworms, which also give off light. We also have a bright orange mushroom called the Jack-o-lantern mushroom whose gills glow in the dark. Other animals known to glow are certain jellyfish, comb jellies including the Sea Walnut we see in The Keys, earthworms, squid, and a variety of micro-organisms.
The actual chemical process of a living thing producing light is particularly fascinating to me. Phosphorus used to be believed as the cause of bioluminescence but it is now known to be caused by oxidation. Within the organism, on demand, oxygen (via gas or liquid) is added to a mixture of 3 other compounds: an enzyme and a protein (which are the exact same in every bioluminescent organism) plus the 3rd compound which varies depending on the organism. For jellyfish it's calcium, earthworms use peroxide, and fireflies use ATP (adenosine triphosphate).
What particularly delights me as a science-loving pastor are the names of the enzyme and protein that must be used by every single living organism if it is going to produce light. The name of the enzyme is luciferase and the name of the protein is luciferin. Many of us quickly see the root word "lucifer" in both of those words. Though Lucifer means "light-bearer" and is the Latin name for Venus, the bright "star", Lucifer is also a well known name given to Satan, the once bright angel fallen from heaven and now the Prince of Darkness.
So for me now, whenever I see a firefly or the glow in the night waters of The Keys, I am delighted every time to recall that luciferase & luciferin have given way to darkness-piercing light in much the same way that Satan has been defeated by the true Morning Star, the Light of the World, Jesus Christ.
Perhaps your thoughts will head the same direction from now on every time you see some special creature displaying it's Life Light, it's wonderful, glowing, bioluminescence.

Blending In: The Art of Camoflauge

As a pastor with a shepherd's heart, I am always aware of guests visiting our church and sensitive to what they may be feeling their first time inside our doors. Some have just moved to the area and are "church shopping": visiting a number of local churches and getting a feel for each one. Some are eager to find a place to roll their sleeves up and jump into serving at their new church home and seemingly anxious to meet everyone. Others have had little church experience recently, or ever, and are very cautiously sticking their toes in the water to see what this "church thing" is all about. Still others have had a past, painful church experience and come determined to stay very unattached, testing to see if this place could truly be safe.
Guests in the last two categories usually have an obvious plan for staying invisible; seeking to blend into the surroundings while they are feeling vulnerable.
This hiding due to a feeling of vulnerability is an extremely common phenomenon in the ocean. We see camouflage on land as well but it seems far more frequent under water. The food chain feels like a much more pervasive reality under the sea and as a result, the observant diver can witness a plethora of delightful examples of the vulnerable blending into their surroundings.
Here are a couple of examples of camouflage we see most frequently near shore in the Florida Keys.

Yellow-spotted Stingray

The Yellow-spotted Stingray is a notoriously expert hider. See how it's coloring and pattern help it blend well into the algae and sand mix on the bottom. The only way to see it is by the distinctive outline. Many times the stingray will solve that problem by wiggling it's large pectoral fins throwing sand, often covering the animal to the point where only the eyes are sticking above the sand. These animals do not attack. They are in fact very docile allowing for very close viewing but it's always a good idea to watch your step in sandy areas so you don't accidentally step on a submerged sting ray.

scorpionfish

The Scorpionfish is another fish that is perfectly designed to hide on the bottom of the ocean. Like the stingray, scorpionfish can give a nasty sting to the careless diver who places their foot or hand down without paying careful attention to what they are doing. Not only does the color pattern help the scorpionfish to blend in but they have an incredible array of growths shooting out in every which way perfectly mimicking the silt-covered algae on the bottom where they so often sit motionlessly.




Secretive critters such as these are why we are always urging our students to move very slowly through the water, learning to examine every sponge, coral, rock, algae, blade of grass and patch of sand. Life is hiding almost everywhere in the sea! And we are always pleased when students take our counsel to heart and find things that leave their instructors scratching their heads as to how that student ever found such an impossibly hidden animal.
Last year, it was Elsa Miller, from Central Christian, miraculously finding the brittle star Ophiothrix suensonii on the soft coral Pseudopterogorgia. Like this:

Except that the coral's yellow polyps were completely extended like this; blending in with the yellow arms of the brittle star. (by the way, clicking on any photo anywhere on this blog will give you an enlarged view of that photo).

And the arms of the brittle star were intertwined with the coral branches like this. All in combination made the brittle star almost completely invisible. The colors where an exact match. The only hint at all to the eye was the line of the brittle star arms forming lines that didn't quite match up with the rest of the coral but this was truly one of the most remarkable examples of careful observation that I have ever seen.

Another fine discovery was made in our lab. Each year we bring a variety of algae back to the lab for identification. We also bring in a bucket full of the algae Saragassum which often is found floating in large clumps throughout the ocean. Many organisms rely so heavily on hiding in the Sargassum that they are named by the algae: Sargassum Shrimp, Sargassum Frogfish, Sargassum Nudibranch to name just a few. All have camouflage that blends perfectly into the light brown colored algae so we often sort very carefully for these creatures. Sure enough, after coming up empty on several occasions, we turned up a Sargassum Crab.

Can you find the crab hiding in the center of the bucket on the left? Click on the photo to make it bigger. There is actually a second crab above and to the left of the center crab. On the right is a close-up of a Sargassum Crab. You can easily see how the pattern & colors of the crab make it blend wonderfully into the Sargassum algae.

Several marine animals can actually change their color at will to blend into their surroundings like a chameleon. Last year at Looe Key, I was able to find a fish I had long been looking for due to it's interesting elongated shape and it's habit of swimming vertically instead of horizontally. There, right in the open, swam this bright golden Trumpetfish, doing anything but hiding.
 
Ah, but when they are alarmed and feeling unsafe, the Trumpetfish has the ability to use it's unique swimming style and color-changing gifts in brilliant fashion; choosing locations that make this large fish incredibly hard to see. (right)  Trumpetfish have color-changing cells called chromatophores in their skin. By making the chromatophores of a certain color bigger, Trumpetfish can become a different color as well as change their banding pattern. Chromatophores are connected to the nervous system and controlled by muscle contraction. It takes a lots of energy so the fish don't change colors unless they have to.

Another wonderful marine animal that changes it's colors at will is the squid. In the keys we see the Caribbean Reef Squid. The squid uses the same muscle-controlled chromatophores to change colors. However, squid can also produce light through the amazing process of bioluminescense. But that's a whole other blog in itself. Between color changing and light producing, the squid can bear an incredible array of appearances as need be. The 3 photos above are just a small sampling of the range of appearances a Caribbean Reef Squid can have.
So if you ever have the privilege of snorkeling the Florida Keys or another reef, GO SLOW! Look carefully! You will be amazed at what you see hiding, blending into the background.

Redeeming Algae

The word "redeem" is a very rich, meaningful term for those of us in the Christian faith. Early in the Old Testament, God reveals the idea of the Kinsman Redeemer, one who will vindicate and rescue his needy relative. It is a picture designed to point us beautifully to the rescuing work Jesus would do on the cross many years later.
I had said in my very first post we would talk here about the animals and plants that we see while snorkeling near Long Key in Florida and so it's time to share a bit about some of the marine "plants". (Actually, most of the algae are not classified in the plant kingdom but belong in the kingdom Protista. There are marine plants which have roots like terrestrial plants do. Algae do not have roots but attach to the bottom with finger-like things called rhizoids).
Algae gets a pretty bad rap in freshwater locals like we have here in Ohio. Everyone with a pool, pond, or little fountain is trying to "control" (kill) the algae that so persistently wants to spread in our water. As a result, many species of algae, in these parts, all get lumped together under the less-than-favorable moniker of "Pond Scum".
Ah, but just like it does to other things considered lowly in Ohio (like worms), the sea "redeems" algae. After a week of Marine Biology with us, you will catch yourself before saying "pond scum" and you will (hopefully) never say "seaweed" again.
This is because the snorkeler in the near shore waters of the Florida Keys will lay eyes on many truly beautiful, interesting, and important species of algae.

There are 3 Phyla of algae we observe: Phaeophyta (Brown Algae), Rhodophyta (Red Algae), and Chlorophyta (Green Algae). Interesting brown algae includes Sargassum, which is often seen detached and floating on top of the water due to the air bladders in it's structure, and Dictyota which provides a classic example of a particular animal (Ragged Sea Hare) using a particular alga (Dicyota) for camouflage. Can you tell between the photos on the left which is a clump of Dictyota alga and which is actually a very cool animal called a Ragged Sea Hare? Not surprisingly, the sea hare spends most of it's time in locations where the bottom is covered with Dicyota alga whose y-shaped branches are nearly inseparable from the y-shaped papillae that jut out from the sea hare's body. You can imagine the slow, painstaking observation that is required to find this animal hiding among this alga!
All 3 of the algal groups perform photosynthesis and since there is so much ocean on our planet, algae is believed to produce as much as 87% of our planet's oxygen! Surely they deserve better than being pond scum and seaweed!

Halimeda

Rhipocephalus

The eye-catching beauties among the marine algae are the Green Algae. Very rarely, as you snorkel in The Keys can you look down and not see some species of green alga growing underneath you which is why they are such a crucial piece of the food chain in the ocean. Green marine algae come in a delightful array of shapes and sizes growing up from the sea bottom. Each species has it's own set of animals that prefer to feed on or hide in that particular species of alga. Here are some common ones we find:

Caulurpa

Pencillus

Udotea

Acetabularia

All living things that people discover are given a Latin, scientific name indicating their genus and species. Once a "thing" with a scientific name is observed often enough by non-scientists, it tends to be given what is called a common name that, for our country is in English and often descriptive of how the "thing" looks so we can remember the name more easily. All of the captions under the pictures list the genus of the alga's scientific name. Can you match these common names to the correct genus by their appearance? Mermaid Fan, Shaving Brush, Pine Cone, and Mermaid Wine Glass? Not too hard is it? That's the beauty of common names although common names have flaws as well since different common names spring up in different parts of the world. Both scientific names and common names have their place but it is interesting to find that enough people are looking at and enjoying the beautiful marine algae enough to be giving them common names.
So hopefully, we've helped redeem the algae a bit today and maybe when it warms up and green growth appears on your favorite water spot, you'll think twice before you mutter "pond scum". Everyone needs a little redemption!

The Exquisite Flamingo Tongue

The first time I ever snorkeled was off an abandoned island off the coast of Belize. It was 1985 and I was spending 3 months in Belize as part of Goshen College's Study Service Trimester. I will never, ever forget the first moment my mask went under the water. The vivid colors! The bizarre shapes branching up from the bottom! So many things vying for my attention! My friend, Jerry Hochstetler, who had just finished studying invertebrate zoology with me dove down below me and came up holding the most beautiful little shell I had ever laid eyes on. 

Cyphoma gibbosum

It's common name was as exotic sounding as the animal appeared: Flamingo Tongue. I marveled at the incredible pattern and colors of this inch long snail.
Many years would pass without me seeing my second Flamingo Tongue. Finally after leading many mini-term trips for Central Christian School, my brother-in-law, Von Schrock reported finding a Flamingo Tongue at Indian Key. Lake Center would be taking our very first trip just two weeks later. Flamingo Tongue would be at the top of my Most Wanted List! Our small group of guys was fortunate enough to find several of these gems that year and we have found Flamingo Tongue every time we have been to Indian Key since (but almost nowhere else).
The Flamingo Tongue's scientific name is Cyphoma gibbosum. It is from the Mollusca phylum in the class Gastropoda. Not all of the Gastropods have large external shells like Cyphoma does but when they do, they are created by a very important part of the snail's anatomy, the mantle. The mantle serves many important functions including secreting calcium carbonate which creates the hard outer shell which in turn provides safety for the soft animal to live in. The term "mantle" comes from the Latin word pallium which means "cloak" or "robe" because many Gastropods can extend their mantle, or robe, entirely covering over their shell much like a robe. Indeed, the brightly colored, polka dot pattern of the Flamingo Tongue is not the shell at all but the mantle extended out over the shell. Many a novice collector has unknowingly grabbed a Flamingo Tongue thinking they were taking a beautiful shell home only to end up with a relatively plain shell after the animal has died.

If you look closely at the above photo, you can see the mantle is slightly opened just at the peak of the shell. Here is a photo of some Flamingo Tongue shells; still quite pretty but not nearly so dramatic. These small snails feed almost exclusively on the polyps of the gorgonians, the soft corals. Often they are found on sea fans in the deeper reefs but in the shallower water of Indian Key we find them feeding on the genera Pterogorgia and Pseudopterogorgia. Below is a photo taken with a simple underwater point and shoot digital camera by student Hannah Horner last year at Indian Key.

Flamingo Tongue on Pterogorgia at Indian Key

 Notice in the photo that on most of the left side of the purple coral branches, you can observe the tiny yellow coral polyps which are the colonial animals that build the purple, branching structure you see. However, you can see that on the right side of the coral where the Flamingo Tongue is feeding, all the polyps are withdrawn, trying to avoid being eaten by the hungry snail. Normally there are few enough snails that they live in good balance with the corals but recently there was a population explosion of Flamingo Tongue in Puerto Rico that is putting the local soft coral population at risk. A video link showing this unusual problem can be found here
Cyphoma gibbsom is not the only species of Cyphoma that can be found at Indian Key. Two years ago at Indian Key, Central Christian's class had found an exceptional count of Flamingo Tongue there. Then two weeks later, Lake Center's class could find no live Cyphoma but oddly found 15 or 20 dead Cyphoma shells on ocean floor. However, we noticed that several of the shells we found were a bit longer and more white instead of the orange color Cyphoma gibbsom shows. A little research showed that these shells were the much less common Cyphoma mcgintyi, the Spotted Cyphoma and the following year we were able two discover two living Spotted Cyphoma with their snazzy mantles covered with purple polka dots bordered in red.

Cyphoma mcgintyi

Cyphoma signatum

Now we are in hot pursuit of the even more rare Fingerprint Cyphoma, Cyphoma signatum. Ice cream sundae for sure to the watchful diver who turns that one up!

The Magic of the Ocean at Night

"Nighttime sharpens, heightens each sensation. Darkness stirs and wakes imagination." So begins my favorite song from the Phantom of the Opera, "Music of the Night."
The underwater world is always a wonder to me but never more so than under the canopy of darkness. Many delights are observable at no other time than nighttime so our midweek night dive is fast becoming my favorite.
Almost everyone has to face some fears when they begin snorkeling in the ocean. Many fear sharks, some fear drowning, some fear being bit or stung, some just sense having less control than when standing on dry ground. We always get in several long days of snorkeling before we attempt our night dive in the middle of the week because jumping into the ocean and only being able to see what your small, underwater flashlight illuminates adds a whole new twist to a diver's fear level but the rewards to those who conquer their fears are always well worth it.
"Slowly, gently night unfurls its splendor" begins the second stanza of "Music of the Night" and marvelously describes what happens to ocean life as darkness falls. During the light of day, everything is a hiding place for the invertebrates wanting not to be eaten by fish and other creatures cruising around. Coral, sponges, rocks, holes in the sand, and even trash like bottles, discarded pipes, old lobster crates, cement blocks, and whatever else falls to the bottom of the sea all are put to use as hiding places during the day.
Ah, but at night most of the fish are sound asleep and the invertebrates come out to play and feed. Yes, I did say the fish are asleep and yes this is very cool to see. Depending on the species, the sleeping fish may be floating right near the surface, directly on the sandy bottom, or my favorite, sleeping suspended right in the middle of the water column. I have swam up to a 4 foot long sleeping barracuda and poked it in its ribs and watched it take off like it was shot out of a cannon. Not the most considerate thing to do to the fish but certainly an eye-opening once in a lifetime sight!

Decorator Crab

But as I said, while the fish are sleeping away, the invertebrates will play and this is quickly visible to the night diver. Caribbean Spiny Lobsters are out walking around everywhere. Crabs of all varieties are out of their holes and climbing over every sponge, coral, and clump of algae. Recently we have been seeing many decorator crabs on our night dives. Decorator crabs are a fascinating, poorly understood group of crabs that gather other living organisms (anemones, sponges, corals, hydroids, alga) and attach them to themselves to provide camouflage, defense, and even food when supplies become short. Coral polyps which are withdrawn during the day are fully exposed, giving the corals a much softer, more colorful appearance as they filter the passing water for morsels of food. The water column itself is often alive with tiny invertebrates. One night there may be tiny jellyfish everywhere, another night you may catch glimpses of the red eyes of tiny shrimp always in the peripheral vision of your light beam. Always there are many things active that are normally quiet and hidden in the glare of day.

Echinaster Sea Star

Gulf Toadfish

Harlequin Pipefish

Surprise and discovery are the rule of thumb on these dives as we are constantly finding new and unexpected things. Last year a sea star of the genus Echinaster was found out in the open. Also out in numbers were the strange looking and normally reclusive Toadfishes. An exquisite Harlequin Pipefish, closely related to the seahorses, was found wrapped around a soft coral. During Lake Center's first ever night dive, we found what appeared to be a Giant Tube-Dwelling Anemone. A species we have never seen before or since. In the last 2 years in the same area of coral stubble, we have found several sets of strange tentacles reaching up through the coral that seem to belong to a bizarre, rare, very large worm called the Long-Bristle Eunice which when seen in its entirety looks something akin to a sea monster. Clearly it's time to expect the unexpected at night.
Above all these wonderful finds we've had during our night dives for me stands one particular find. Many marine animals use amazing camouflage to stay alive underwater. Perhaps the ultimate masters are the frogfish. These masters of disguise sit motionless, blending into the coral, algae, or sand they are sitting on during the day and are so well hidden I assumed I would never lay eyes on one. Incredibly, a student found one suspended in mid-column right at eye level in 4 feet of water.

Striated Frogfish

This was the Striated Frogfish, complete with a strange front fin called an illicium which has a lure (called an esca) on the end just like the nasty fish in the deep in Finding Nemo.
Surely darkness does stir and wake imagination and in the sea at night, reality lives up to our dancing imaginations.

Video Summary of our Class in the Keys

A while back I put together an 8 minute video of photos and videos from previous classes we've taken to the keys. The video was made to explain to students considering whether or not to go what the class is all about. It should give all of you a nice idea of where we go and what we do. You can also go to my facebook page and see underwater photos taken by one of the students here. In this photo album, I label many of the common plants and animals as seen on the locations we dive.
More, mostly above water photos of previous trips can be found here, here, and here. Enjoy!

A Beautiful Slug?

As I mentioned last time, the Craig Key Channel swim offers an opportunity to float on your stomach and let the currents drift you over top of some pretty impressive, large sea creatures out in the middle of the channel. But even more fun for me is to go inch by inch over the rocks and mangroves along the shore. The mangrove roots seem to be a nursery for many juvenile fish. Angelfish, parrotfish, groupers, puddingwives, scorpionfish, the invasive lionfish, green morays, and especially species of colorfully decorated damselfish all hide among the roots and rocks and young fish seem especially prevalent here. More fascinating still are the array of invertebrates that live in the channel. Shrimp, sea cucumbers, sea stars, brittle stars, sponges, hard & soft corals, anemones, zoanthids, tunicates, feather duster worms, and many molluscs including the beautiful conchs and cowries are just a few of the fascinating invertebrates regularly seen on the Craig Key Channel dive.

Atlantic Deer Cowrie

Cushion Sea Star (genus Oreaster)

Every dive we record all the species of plants and animals we are able to identify and the list from a Craig Key Channel Dive is always long and interesting.
But there is one unique animal we always make a special effort to see every time we swim the channel. It is a species we see almost no place else. It is called the Lettuce Sea Slug, or Elysia crispata (formally Tridachia crispata) It is usually not much more than an inch long and usually shows some combination of green, yellow, and purple hues. It loves to hide on the large, crunchy Halimeda algae beds where it is almost impossible to find due to it's nearly foolproof camouflage. Some of the slugs however crawl onto the rocks and mangrove roots where they are easier to spot and when they are found, they quickly become one of the favorites of most students.
The first thing that catches a diver's eye is the slug's frilly design on it's back. These fancy ruffles which look a bit like a head of lettuce and give the slug it's name, are actually folds of tissue called parapodia. These skin folds provide two key life functions for Elysia, one which is a particularly fascinating handiwork of the Creator.
The thoughtful observer would quickly guess that the design of these parapodia is likely increasing the surface area for some reason and this is the case. The ruffles function much like gills, taking in oxygen and releasing carbon dioxide so the design aids in gas transfer.
More fascinating still, these parapodia function in providing the animal food. The lettuce slug feeds by sucking the cytoplasm out of cells of algae. Not all the cytoplasm, however, is digested. The slugs are able to keep the chloroplasts intact. The chloroplasts are the structures within the algal cells that carry out photosynthesis.

chloroplasts

Elysia then stores the intact, stolen chloroplasts in it's frilly parapodia and there, incredibly, the chloroplasts continue to function, gathering sunlight and converting it to food which, rather than feeding the algal cells, instead feeds the crafty slug. So incredibly, this creature can feed by sticking food in it's mouth like an animal AND it can feed by gathering sunlight like a plant! In fact, some have called Elysia a fusion of plant and animal. That's pretty cool! Actually, the Lettuce Sea Slug is a mollusc, particularly from the Class Gastropoda. It is basically a snail without a shell. Whatever you call it though, the Lettuce Sea Slug is one of those creatures that we find that is incredibly beautiful, but when you learn a bit more about it, you discover it is as interesting as it is sweet to look at.

Channel Surfing

One of the underestimated benefits (if I may say so) of taking Marine Biology with Lake Center is that you get to dive with guides that have years and years of exploring the near shore waters close to Layton. Obviously, there is water everywhere in the Florida Keys so discovering the most interesting places to snorkel only comes by jumping in at many, many places through the years and finding the best spots.
We still do an occasional exploration of a new dive location but most of the places we go are time-tested favorites.
One such favorite is shown in the satellite photo above. We call it the Craig Key Channel Swim and as you can see, it is situated right up against US Rt 1. Hundreds of cars speed right past this wonderful spot every day not knowing what they are missing just a few yards from their vehicle. If you look at the bottom half of the photo you see a large, grayish area. This is an expansive turtle grass bed. This is a very shallow flat where at low tide, the water barely rises above the tops of the grass. The bottom on the flat is quite muddy and not firm so even though there are some interesting things that can be found here, we generally stay away from this very shallow area.
Ah, but that narrow blue-green area right below the road that looks about as wide as the road, that is another habitat altogether. This is a classic channel. The ocean seeks to find the path of least resistance as it cuts it's way through the shallows of the keys and back out into the ocean depths and through the years, these cuts create channels where the water is deeper, cooler, and moving faster as the ocean squeezes, if you will, through these channels.
As a result, larger sea creatures you would never find in the shallow flats can be found cruising from one deep area to the next via these channels. And that is exactly what we see during this swim. Goliath Grouper, Spotted Eagle Ray, Tarpon, Barracuda, Snook, & Southern Blue Sting Ray are all seen out in the deep portion of the channel which can be 15' deep during high tide.

Spotted Eagle Ray

Goliath Grouper

It is while searching the deep center of the channel that the term "channel surfing" can be applied. If you have avoided the slack period (the time when the tide is changing from coming in to going out or vice versa--at this time there is almost no current here) you will get to experience a fairly strong current pulling you through the channel. It is a new feeling for most Ohioans to swim out to the middle of the channel and then to surf, or drift at a surprising speed down through the channel, watching for the large sea creatures below you. The only problem you must adjust to is that if there is something interesting you want to dive down to investigate you must see it far enough ahead of you and compensate for the speed you are traveling horizontally and start your dive down well ahead of your target. Channel surfing is a very cool sensation!
To enjoy the channel surfing, your guides must always first determine the direction of the current because, again, depending on the tide, the current may be ripping east to west or west to east. Usually we look first for the brown algae of the genus Sargassum. This is an abundant algae that has air bladders as part of its structure so when boats or other things tear it from the bottom, it floats in the water. By looking to see which way the Sargassum is floating through the channel, we can usually determine the direction of the current. Sometimes by looking down from the road, we will see schools of tarpon and they usually will be swimming with the current. Always though, the leader will get into the water to be sure we are 100% certain about the direction.
Then we simply walk along the shore and enter the water at a point where channel surfing the current will take us right back to the car.
But channel surfing is not the end of the Craig Key Channel Swim story. There are shallow edges to the channel that are full of smaller, fascinating things that I enjoy even more than the large things cruising the deep. But we'll leave the story of the Craig Key shallows for next time.
So the next time you're using the remote to power through all the stations, remember there is a far more enjoyable channel surfing waiting for you in the fabulous Florida Keys.

Warm Thoughts on a Cold Day

What better day to write about the Florida Keys than a day when my home weather station keeps hitting minus 15 wind chill even at mid-afternoon. Usually the temperature in Layton is right around 90 at this time of the day when we are down there in the middle of June. The water temperature is usually in the low to mid 80s by then allowing even those who get cold very easily to be very comfortable for long stays in the water.
Water temperature is a crucial factor in the growth of the animals which build the reefs we love so much: the hard corals. These corals grow well in the Keys because the water temperature there stays from the mid 60's in winter to the mid 80's in summer. If the water rises to 90 degrees or dips down below 60, the coral can bleach and die within days.
This was exactly the case in January of 2010 when a serious cold spell caused the ocean temps to stay in the low to mid 50's around the Keys for at least a week.
One of our favorite dives is at a wonderful place called Indian Key. This spot is delightful for a number of reasons but one of the more special features has been the very large Starlet Coral mounds.

These coral heads are interesting animals in and of themselves but what makes them such an attraction at Indian Key is the array of animals that live on and around them: Neon Gobies sitting on the top. Christmas Tree worms sticking out all over. Slate-pencil urchins hiding underneath and even an occasional octopus is found hiding in the crevices.

Christmas Tree Worm

Neon Goby

However, the coral heads of Indian Key took a hard hit in January of 2010. By June of 2010, many of the formations were partially or completely bleached white from the freeze. By June of 2011, a number of the formations had disappeared completely. 

Slate-pencil Urchin

Encouragingly, a number of the larger formations that had survived were showing new areas of growth and many, many tiny new formations were littering the ground. The new growth in the larger formations gave us hope to search for perhaps our favorite resident of Indian Key's coral heads, the Green Moray. This eel loves to hide on the sandy bottom under the overhangs of of the coral heads and the snorkeler willing to dive down and search the holes and underneath these coral formations at Indian Key was almost always certain to find 3 or 4 of these interesting animals. A Green Moray can reach 6 feet long and appears to be one huge muscle. The eel is actually gray colored but is entirely covered by a bright green mucous. Often called a sea serpent, the Green Moray is actually a sleek fish with no scales. Not uncommonly, an investigating diver will come face to face with these unique fish which can be a bit unnerving because invariably their mouths are open revealing an impressive set of teeth. But morays are very non-aggressive animals and what often looks like a move to bite someone is just the moray sucking water into it's mouth which passes over it's gills and allows the fish to breath.

In 2010, for the first time in many years, we found no Green Morays at Indian Key and despite much looking in 2011, we again found none (although we had great looks at them on other dives).

However, one student who was constantly diving and looking carefully for morays did make an exciting discovery. He found an eel doing what they love to do: sticking his head out of a hole in the bottom of the Starlet Coral.

Only this was no Green Moray. This was the much more uncommon Goldentail Moray.

The Goldentail is not as massive a fish as the Green Moray. It grows to little more than 2 feet long. But what it lacks in size it more than makes up for with it's fine, golden markings and it's rarity. Yet another animal finding its home in the wonderful hard coral formations of Indian Key.

I could enjoy some 85 degree water at Indian Key right about now...

The Thrill of Discovery

Each year that we take another group of students to Layton for a week of Marine Biology, I create a "Most Wanted List". This list is made up of species which are known to live in the surrounding waters, but that I have never yet seen or at least have not seen in many years. Usually a reward of ice cream or some similar fare is offered to the underwater sleuth that discovers any of the organisms on my list. 

Perhaps at the very top of my list during our last trip was a seahorse. Our favorites tend to be invertebrates but the seahorse's rare status along with it's unique beauty placed this charming creature very high among the things I longed to see.
Half way through the week, our group was doing our annual night dive. This is where we all snorkel out from shore after it is completely dark with only small, underwater flashlights in hand.
Due to new diver's anxieties of being in the ocean in pitch blackness, we always stay in very close-knit groups with each group staying near to the others.
It is always a little touch and go as to what you can hear while you are snorkeling but this night, the stillness was broken by a very clear, very loud sentence not 15 yards from me. The voice belonged to Charles McMullen and the sentence was, "I found a seahorse!" Needless to say, this leader made a very abrupt turn towards Charles and covered the 15 yards in a time that would've made Michael Phelps proud. Sure enough, there was the first live seahorse I had ever laid eyes on, slowly waving his tiny dorsal fin to maintain it's balance against the light current while holding on to a purple pterogorgia coral with it's tail.
Soon everyone from all of the small groups were floating in a circle around the searhorse and it's coral anchor and you could literally hear "oohs" and "aahs" coming through snorkel tubes all around. Because of their tiny fins, seahorses are pretty lame when it comes to swimming. Though they can straighten out and swim horizontally like a regular fish (which this one eventually did) they still can barely make headway, even though their little dorsal fin can be wiggled 35 times per second. As a result, they must rely completely on camouflage for defense.

As an example, here is a photo taken last year by one of Central Christian's student's, Hannah Horner on a dive where we amazingly found 3 or 4 seahorses. Can you pick it out?
Anyway, back to our story of discovering our very first seahorse. After everyone had oohed and aahed for several minutes, it appeared to me that this fish was quite tame, it showed no reaction to the 10 shark-like things floating in a circle around it so I reached down and gently lifted it off the coral and placed the seahorse standing on it's curled tail in the palm of my hand under water. We were then able to carefully pass the seahorse around the circle under water to each person in the group. It would either rest upright in our palms or curl it's tail around our fingers. Finally, we placed it back near it's home soft coral where it straightened out and swam like it's close relatives, the pipefish, and reattached to the coral, blending in like it had before.
In addition to being such calm, gentle, beautiful creations, the seahorses are amazing in several other regards. These little guys have very healthy appetites. Though they are restricted to catching only what floats by as they hang on to a coral or blade of grass, a single seahorse has been observed catching and eating 3000 brine shrimp in a single day!
More uniquely the seahorses are one of the very few animals where the male carries their unborn young. The males possess a brood pouch on their ventral side. The female deposits her eggs into the male's pouch where they are internally fertilized and carried until he releases the fully-formed young into the water 20-21 days after the eggs were deposited.
All 5 seahorses that we have now found in the last two years have been the species Hippocampus Erectus, the Lined Seahorse. Though this species can be gray, red, green, or orange, all 5 we have found have been primarily black and all 5 have appeared to be the larger males all nearing 6" in length.
But though I have now layed eyes on 5 different seahorses, I will never forgot the thrill of the first one; the joy of discovery.
Thanks Charles. I hope you enjoyed your ice cream cone in Key West.

Can't We All Just Get Along?

Because the seas are "teeming with life", the marine environment is unusually full of animals sharing space in a variety of symbiotic relationships. Many of these are visible to the naked eye and a delight to observe.
"Finding Nemo" is one of my all time favorite movies and though the setting is Australia instead of the Florida Keys, much of what is depicted in the cartoon quite accurately represents what is found in reefs around the world, including the Keys.
In the beginning of the movie, Marlin and his family are living in the safety of a large anemone and in the Florida reefs we find a variety of similar symbiotic relationships happening with anemones.

One of the largest and most common anemones in Florida is the Giant Caribbean Sea Anemone, Condylactis gigantea . Usually we will find 1-5 of these beautiful animals on a typical dive at the work site. These creatures' tentacles come in a variety of colors: all purple, green, brown, orange or blue. Most often they are cream-colored with pink or purple tips. Usually hidden is their stocky, fleshy body column which is usually attached to a rock, coral, or some other hard surface on the bottom.
Anemones belong to the phylum Cnidaria which includes the corals and jellyfish. These animals all possess a unique type of cell called nematocysts which enable the animals to defend or feed themselves by the harpooning action of these stinging cells. These nematocysts are lethal to many small marine animals but the callouses of most snorkeler's fingers are thick enough so that no sting is felt if you touch their tentacles. Usually there is just a sticky sensation when the tentacles stick to your skin as the animal attempts to inject its mini harpoons into your finger.

This stinging characteristic of Condylactis makes it all the more interesting as to how creatures come to live among the nematocyst-loaded tentacles and yet there is exactly where other species live. If the snorkeler waits patiently and looks closely at the tentacles of any Condylactis they find, they will almost always be rewarded with a small (1/2 inch long) but BEAUTIFUL shrimp, most often a Spotted Cleaner Shrimp like the one in the macro photo above. The pictured shrimp is shown standing on the tentacles of a Condylactis. You can see the white spots on the tentacles which are the stinging cells.
For about 2 1/2 hours after a shrimp first moves into an anemone, the anemone makes aggressive actions and the shrimp defensive actions towards each other. But then anemone relaxes and the shrimp appears to develop a membrane which protects it from the sting. Shrimp that have been removed and washed off in studies need another 2 1/2 hour acclimation period to re-develop this protection.
After the adjustment hours are over, the anemone provides protected shelter for the tiny shrimp and the shrimp appears to clean the anemone as well as foster the growth of another organism which shares a vital symbiosis with the anemone, zooxanthellae, a tiny type of algae crucial to the anemone's survival and also often providing the pigment which colors the anemone. 
Those of us created in the image of God could take a few cues from these two invertebrates, very different from each other yet living together in a way that both are blessed by the actions of the other. And once again, the blue waters of the Keys reveal two fascinating creatures waiting to delight the observant diver and testify of a very creative Creator.

A Spectacular Worm

Trying to decide which creature or place from the waters around Long Key to share about first is a challenging task so I'm choosing what will probably be the first animal you will see in the first location we dive at each year during mini-term. The dive site we simply call the worksite. It is an easy place to get in the water for the first time and students have been studying marine life here for years.
The sattelite image pictured above gives an overview of our home base for the week. On the right side is a yellow marker pointing to the roof of the Goshen College Facility where we live for the week. You can see that it boarders the Zane Gray creek or channel that cuts through Long Key. Turtles, sharks, Goliath Groupers and many other interesting things swim right under our dock which overlooks this channel.
On the left side of the image you see the yellow marker which marks the worksite. To reach it we take a 10 minute walk up South Layton Drive, left along Rt 1, and then turn right on a path that cuts through the mangroves to the bayside waters of the ocean. You can see the dark areas under the clear blue water that provide structure (coral, rocks, sponges, grasses) that many of the interesting animals we study live in.
As I mentioned, the last couple years at least, the first animal you are likely to notice as you put your mask under the water is, of all things, a worm. Now that may not sound very exciting to you as your mind pictures the earthworms all over your driveway after a heavy rain here in Ohio but marine worms are an altogether different sort. We see many worms that have appendeges that come off their heads that look look like Christmas trees, others that can be 6 feet long, some that sting like fire, and some that are all the colors of the rainbow. These are from the phylum Annelida and most worms that we  see are segmented worms from the class Polychaeta.
The worm that comes to view very quickly at the worksite is called the Medusa Worm. More often we simply call it Loimia. It's full scientific name is Loimia medusa. Medusa you may recall was the beautiful lady from Greek mythology whose pride in her beauty eventually caused Athena to turn Medusa's lovely long hair into snakes.
It is the extremely long, snake-like "hair" from Loimia's head that gives it the name Medusa.

Of course a worm has no hair but what the diver is seeing are bluish, translucent tentacles that can be as long as 2 feet. To the delight of the student snorkeling in the shallow waters (perhaps 3' deep) at the worksite, not only are Loimia's tentacles interesting to see but if you give any one of the tentacles the slightest touch, they immediately begin to be retracted back into the worms hideout. And a hideout it is. You will likely never lay eyes on the actual Medusa Worm. These worms live in self-constructed tubes which they build out of sand and their own mucus. This tube-building only takes about a half an hour where the young worm grabs sand particles with it's tentacles, brings them back to it's mouth, smears its gooey mucus on the sand, and then builds the tube around itself about twice as long as it's young body so that it can continue to grow inside the tube it has built. They must not be claustrophobic because they live the rest of their lives inside this tube with only their long tentacles reaching out into the ocean searching for it's food which is usually tiny pieces of waste matter or small, decomposing animals. When it finds a tasty morsel, if it is small enough, it slides the food down it's U-shaped tentacle back into it's mouth near the top of it's sandy tube. If the food is too large for this, it will drag the food back to it's mouth by retracting that tentacle.

So the next time you wade into the water off of Long Key, before you go chasing one of the flashy, brightly colored fish, look down and enjoy the amazing Medusa Worm, Loimia medusa.