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.