Bubble Coral

We have displayed a lot of photographs of reef scenes on The Right Blue. Reefs are formed by corals. The stony corals in the order Scleractinia are the reef-building corals that secrete calcareous skeletons for their polyps, which accumulate over time to become the hard framework of reefs.

We have posted quite a few photos of different kinds of soft corals, ranging from 'broccoli coral' and other Nephtheids to sea fans. Soft corals generally are more colorful and showy, and so they often are more attractive subjects for photography, but without hard corals, there would be no coral reefs. Until now, we haven't really focused much on stony corals, so we thought it was time we introduced some of the more interesting ones to readers of The Right Blue.

Some hard coral colonies form massive lumpy structures that look much like rock. Other stony corals form into fingers, pillars, antler-like branches, or even structures that look like plates. The ridged ones commonly referred to as 'brain coral' belong to the stony coral group, too.

One of the more unusual-looking stony corals we know about is Bubble Coral, an organism in the family Caryophyliidae. The first photo on this page shows a large colony of Bubble Coral on a reef in the Red Sea. If you click on the photo to enlarge it, you will see clusters of what look like bubbles -- thus the common name. Those bubbles, or 'vesicles' as they are properly called, are little balloon-like structures with rubbery skin that inflate during the day.

At left is a macro photo of the vesicles. The species in these photos, Plerogyra sinuosa, is quite common in the Red Sea. Usually it is found on steep slopes or on the vertical walls of underwater cliffs at depths of about 15 meters (50 feet) to about 40 meters (130 feet). I shot the first two photos on this page at Ras Mohammed, a well-known reef at the tip of the Sinai Peninsula.

I took the third photo on this page during a night dive off the coast of Tiran Island, which is situated at the mouth of the Gulf of Aqaba. Although we are not 100% certain, we believe that the organism in the photo is Bubble Coral of the same species as the photos above. Unfortunately, we did not get to return to the same spot in daylight to verify that this was indeed Plerogyra sinuosa.

At night, Bubble Coral looks very different than it does during daylight hours. The Bubble Coral's vesicles deflate, exposing its tentacles and its mouth.

In the photo at right you can see what appear to be the partially deflated vesicles, as well as the little tentacles. The tentacles can sting.

By the way, the vesicles of this species usually are whitish, often with striations of grey or very pale blue. They are translucent, and can look slightly opalescent. We have seen Bubble Coral elsewhere with a golden or greenish tinge. Next time we'll show you some more Bubble Coral, this time from Indonesia. The Bubble Coral we saw there had some 'extras' that led us to think of it as Bubble Coral Plus.

Crinoids - Also Known As Feather Stars

In the previous post, about our final dives on the wreck of the Zenobia, I mentioned that we saw crinoids inside the shipwreck. As I wrote that, I realized that many readers, and especially non-divers, probably had never seen or even heard of crinoids. They're strange creatures, and I was hard pressed to describe them for that story, so I thought it would be a good idea to show readers of The Right Blue what a crinoid looks like.

The photos on this page show a crinoid known as Klunzinger's Feather Star (Lamprometra klunzingeri), a species found commonly in the Red Sea. This is not the species we saw inside the Zenobia, but these photos should work well to illustrate what a crinoid is like.

Crinoids belong to the same phylum (Echinodermata) as sea stars and urchins. The phylum name means "spiny skinned" and most members of the phylum do have some kind of spiny structures on their outer coverings.

The crinoids have feathery arms, which are jointed. They can (and do) bend every which way. The arms have rows of protrusions, called pinnules, which run the length of the arm, making them resemble feathers. The crinoids catch their food by extending their arms like a fan. Bits of plankton are caught on the pinnules.

These creatures also have a set of appendages, called cirri, that serve as feet. They can move along on the cirri a little bit, but they also use their feathery arms to propel themselves. Sometimes they bend their arms down in a sort of arc, and use them like extra legs to skitter across sand or other flat surfaces. They use their cirri to hold on tightly to whatever they decide to perch upon.

There are teeny tiny hooks on their ends of the cirri, which help them to grab onto their perch. We have seen these actually puncture a sponge enough to leave a scar. I should also add that, on occasion, we have attempted to move a crinoid from one location to another. It's fairly easy to put a gloved finger next to a crinoid's little feet, and nudge it to perch there. The trouble comes in getting the crinoid to release its hold on that gloved finger again!

Crinoids are nocturnal creatures. They fold themselves up into a ball and hide in crevices in the reef during daylight hours. They usually emerge from their hiding places at dusk, and situate themselves on a favorite perch -- on coral, a large sponge, a sea fan -- wherever they can anchor themselves well. Then they unfold their feathery arms and feed all night, returning again to their hiding places at first light.

Crinoids are sensitive to light. When they are exposed to a bright light, they immediately begin to fold in their arms. For this reason, it is sometimes difficult to photograph them in their full glory, with all their arms completely outstretched. Crinoids are fairly plentiful on many reefs, so they are relatively easy to find during night dives. However what often happens is, we shine our lights around and spot a lovely crinoid, but as soon as it senses the light beam it begins to curl up. So, we switch off our lights and wait. Eventually the crinoid will unfold again, but then the photographer is lucky to get more than one or two shots before the light from the camera's strobe prompts the crinoid to fold into itself again. It takes patience to photograph crinoids.

The two photographs on this page were shot in quick succession. In the first photo, the crinoid's arms are fully extended. (Take note of its little cirri, hanging onto the coral it has chosen as a perch.) In the second photograph, the crinoid already is reacting to the light emitted by the flash during the first shot, so it's beginning to curl up. I photographed this crinoid during a night dive in the Red Sea, off the coast of Egypt's Sinai Peninsula. [Click on the photos to enlarge.]

Do Not Disturb: Sleeping Fish

We all need our rest, and so do the fish in the sea. Fish don't sleep exactly like we do. For one thing, they don't have eyelids, so they can't close their eyes. Nevertheless, most fish we know about do take their rest for some part of the day or night, on a fairly regular schedule.

Some fish -- especially pelagics -- hunt at night, and rest during the day. Most reef fish are very busy during the day, so they rest at night. They stop moving about and enter a sleep-like state. While they are resting, they are generally sluggish and not very alert. We try our best not to startle them or disturb their rest during our night dives.

Some fish lie on the bottom to rest, while others hang motionless in the water column. Small fish, in particular, often hide while they are in their somnolent state so that their predators can't find them and eat them. Staying out in the open to rest definitely would give their predators an unfair advantage. In the first photo on this page, a tiny fish called a Pygmy Toby (Canthigaster pygmaea) has snuggled itself amongst corals and sponges to "sleep."

In the second photo, a small fish has chosen to settle into a stand of fire coral to takes its rest. We're not sure what species of fish this is, although the shape suggests that it is some kind of Damselfish.

In addition to hiding, another strategy that many fish use to discourage predation while they rest is to change color. Their color may darken or become mottled during periods of rest, helping them to blend in with their environmental background.

Some species of Parrotfish hide themselves by spinning a slimy cocoon around themselves. The mucous cocoon is secreted from an organ in the head of the Parrotfish. (Sorry, I don't have a photo handy.) It is thought that, in addition to hiding the fish, the cocoon also masks the animals' scent, making it harder for predators to locate them.

Both of the images on this page were captured during night dives in the Red Sea, along the coast of the Sinai Peninsula.

Nephtheid Soft Corals - Pale Pastels

In the past several posts, we've been displaying images of soft corals of the Nephtheidae family. To soothe any damage we may have inflicted on our readers' retinas with yesterday's collection of corals with fiery colors, today we're presenting images of Nephtheid corals in pale pastel colors.

By the way, the species of a Nephtheid soft coral cannot be determined merely by looking at the colors. Corals of a particular species in this family may come in a variety of colors.

All of the corals on this page, as well as on yesterday's post, belong to the genus Dendronephthya, but we're not certain of the species. In fact, I have been told by a marine biologist friend who studies these corals, that the only reliable way (short of DNA analysis) to identify a species of Dendronephthya is by examining certain internal structures, called spicules, with a microscope. In other words, it's next to impossible to reliably determine the species in the field.

For our purposes, we don't mind that we can't be sure of the exact species. When it comes to soft corals, we have been more concerned with collecting images of the different color varieties than with precise species identification. We're content just to know that these are Nephtheids.

At first glance, the more brightly colored varieties certainly are impressive, but we think there is something appealing about the pastels, too. The paler colors suggest a certain fragility, perhaps.

The stalks of almost all of these corals are somewhat translucent. But take a look at the macro image at right: The stalk is nearly transparent! (To see even more detail, you can click on any of the photos on this page to enlarge.)

Some of the corals in this family have greenish coloration, making them resemble plants. A common nickname for those varieties is Broccoli Coral. Other Nephtheid soft corals are sometimes referred to as Carnation Coral. The series of images below may give you an idea of why they acquired this common name.

I took all of the photos on this page while diving in the Red Sea, at reefs along the Sinai Peninsula. I hope you enjoy them.

Nephtheid Soft Corals - Fire in the Night

This past week I began a series about soft corals in the Nephtheidae family, arguably some of the most beautifully colored marine life on the planet. I mentioned that these corals come in a wide variety of colors, and that while they sometimes look like plants, they are in fact colonies of small animals -- coral polyps -- that arrange themselves in bundles on a stalk or stem.

I have a big problem with these corals: There are so many wonderful colors and varieties that I can't stop taking pictures of them!

The colors range from pastel pale, to richly saturated, to just plain knock-your-eyes-out. Today, we'll show you a few that we call "Fire in the Night" -- brilliant reds, oranges and golds.

I took all of the photos on this page during night dives in the Red Sea. These Nephtheid varieties feed mostly at night, so that is when they are plumped up and looking their best, with their feathery tentacles extended like flower petals. Click on any of the photos to enlarge and see more detail.

The first photo on this page is a a soft coral that had attached itself to the underside of a ledge. This bright red and yellow color combination is, to me, the prototypical "Fire in the Night" color. In case you are wondering, that is not an official name; it's just our name for this color variety.

Next is a macro shot of that same coral. You can see that it is the tentacles of the polyps that are bright red. The stalk itself is relatively pale. Those bright yellow bits on the surface of the stalk are sclerites -- hard structures that help it to hold its shape when it is plumped up. They serve a purpose similar to battens in a sail. They also pose a lighting problem to photographers, since they tend to be more reflective than the rest of the coral.

This next variety is a little less fiery than the one above, but is definitely bright and rich. We call this "Golden Glow." This time it's the stalk and sclerites that are golden, while the tentacles on the polyps are almost white.

A similar variety is the one we call "Hot Peach." It has a yellowish stalk, and bright yellow sclerites, but the flower-like polyps are a rosy pink. The combination of the yellows and pinks make it look quite "peachy," we think.

We'll wind up today with a macro shot of the "Hot Peach" color variety. According to my dive log, this image was captured just after dusk. The photo clearly shows that the tentacles were not fully retracted, but not yet fully extended, either.

These corals are not exactly easy to photograph. First of all, they don't need bright sunlight to prosper, so many of them live in deep water, or under ledges and overhangs, or inside cavelets. So, first the photographer has to find them.

Secondly, since these corals are bushy and branchy, they have many planes, and it's difficult to choose a point of focus. Also, since some parts -- especially those calcareous sclerites -- are more reflective than other parts, lighting them evenly can be a challenge.

Shots like the ones on this page were taken at night. Often there is virtually no ambient light underwater at night. So, the photographer (and her helpful dive companion) must locate the subjects to photograph by shining their handheld searchlights this way and that. It helps a lot if the team already has done at least one thorough survey of the area during daylight!

Next, the photographer composes the shot in light provided by a submersible flashlight. Underwater strobes only light a relatively small area -- so the photographer really has to get in close. Meanwhile we have to mind our buoyancy, depth, elapsed time, and our air supply, among other technicalities. But somehow it all comes together, at least some of the time.

Next time we'll show you some paler specimens of Nephtheid soft corals from our photo collection.

Why I love macro photography: Surprises

About a month ago I said I love macro photography (ultra close-ups) for the fine details that are revealed. The example I gave then was a photo of a tiny hermit crab with hairy legs and turquoise eyes. Neither of those features could be seen with the naked eye -- much less by a pair of eyes behind the faceplate of a dive mask! Those details only became visible when the photo was enlarged.

The photo at right is another example of the kinds of surprises that sometimes appear when macro photos are enlarged. I shot this image of a mushroom-shaped leather coral (Sarcophyton sp.) -- a type of soft coral with a sort of rubbery skin -- because it caught my eye as a perfect specimen, in miniature. Only when the photo was enlarged did we notice the face of the tiny little fish that was hiding under the edge of the leather coral. Click on the photo to enlarge it even more.

This coral specimen was maybe two inches (5 cm) high, so the little fish was too tiny to see clearly. (For the photographers out there, this is a 1:2 image.) We have no idea what species the little fish with the great big eye is, but we surmise it's a juvenile of a reef species. We love the way he's hiding, but peeking out curiously, too. The image was shot during a night dive in the Celebes Sea.

Night shift on the reef

There are nocturnal animals in the sea, just as there are on land. Many marine animals hide all day and only come out at night to hunt, feed, or mate.

The colonial anemone pictured here (Nemanthus annamensis) is one such nocturnal marine animal -- part of the underwater 'night shift' that begins shortly after sunset and lasts until dawn. The only way to see these nocturnal marine creatures is to dive at night.

The anemones in these colonies open as soon as it gets dark. During the night they look like pretty flowers, with their tentacles extended to feed. When morning comes they fold their tentacles inward and each one of the 'flowers' turns into a tightly shut fist. While they are closed during the day they look like nondescript lumps, their nighttime beauty obscured.

The photo was taken during a night dive in the Red Sea, near Sharm el Sheikh, Egypt. If you click on the photo it will enlarge.

Current events, Part 3: Swept away

In the previous two posts I talked about currents in the ocean, and how much fun it can be for divers to ride currents. While drift dives can be wonderful, diving in currents also can create situations ranging from nuisances to something bordering on terror. This is especially so when the currents are unexpected.

One kind of current we don't like to encounter while diving is the downcurrent. Divers need to be in control of their position in the water column, and there are few things more disconcerting than to suddenly feel yourself being pushed down unexpectedly by a mass of water.

We ran into this situation one time while diving off West Caicos, in the Turks and Caicos Islands. Most of the dives in the area are 'wall dives' -- that is, along the face of cliff-like dropoffs. In this case, the top of the dropoff begins at a depth of about 20 meters, and the base of the dropoff is something like 1,000 meters straight down.

The walls there are glorious -- completely encrusted with fans, sea whips, and large sponges of many colors. The wall is the underwater edge of the land, and there's nothing beyond but the open water -- deep and inky blue.

It's quite common to encounter large sharks, rays, and other pelagic fish during wall dives, which is a big part of why wall dives are so appealing. On the other hand, since there is no bottom to land on, or even to use as a reference point, buoyancy control is important. (And, I might add, you definitely don't want to drop anything!)

On this occasion, we were drifting along the wall nearly 30 meters under the surface. We were nearing what had been planned as the deepest point of our dive, so we were carefully minding our instruments for air consumption and depth. We noticed that just ahead there were clumps of bushy sea whips that were fluttering downward. I mean not just hanging downward, but fluttering as if water was being poured over them from above. (See photo.)

I paused to take a photo, and Jerry continued along ahead of me. When I looked away from the camera viewfinder and back at Jerry, I saw that he was not just ahead of me, but more than five meters below me as well -- and his bubbles were going down instead of rising up. He was in a downcurrent. As I watched, Jerry made a sharp turn straight out to sea and kicked hard into the blue. The maneuver worked and he escaped the downdraft, and circled back to the wall. We backtracked in the direction we'd come from rather than risk being pushed deeper again.

Some currents are more a nuisance than anything. We recently unearthed a certain batch of photos I had taken in the Red Sea, and had a good laugh recalling what it took to get the shots. It was during a shallow night dive in a sandy area with a lot of patch reefs -- an area we knew to be particularly rich in little critters of the sort that only emerge from their lairs after dark, so I set up my camera for macro photography. When we entered the water we noticed that there was a current that we hadn't expected, but since we had planned a shallow dive close to the boat, we continued.

We shined our lights around on the sand, and sure enough there were all kinds of interesting photo subjects, especially tiny things. That was the good news. The bad news was that the current sweeping across the sand grew in intensity over the course of the dive.

I spent most of that dive on my belly in the sand, sort of slithering along from one tiny subject to the next. As the current picked up, it wanted to flip me over, so Jerry spent most of the dive lying crosswise across my legs to hold me in place while I operated the camera. I'm sure that if anyone chanced upon us we would have made a really peculiar sight, and who knows what they would have thought we were doing! Really folks, it was just teamwork.

The picture at right is one result of our teamwork that night. You might have to click on the photo to enlarge it in order to see the teeny-tiny nearly transparent crab hiding at the base of the larger creature (called a sea pen - a relative of anemones).

Then there are the terror currents -- the ones that are not only unexpected, but so sudden and strong that they can sweep a diver away. The worst experience we ever had with one of those was at the Brothers Islands in the Red Sea, an area known for strong currents. The current we encountered there one July afternoon challenged us to the maximum.

Our boat had dropped all of the divers in our party along the fringe reef of Little Brother, the smaller of the two islands. The boat then continued to a mooring at the very tip of the island. The plan was for a one-way dive, meandering along the reef to where it ended, at the tip. It was one of those dreamy dives where everything was perfect -- the light was good, the visibility was excellent, the lush reef was spectacular, and there was no current.

Jerry and I were the lead pair of divers. The others were strung out behind us in twos and threes in a parade along the reef. At last we came to the tip of the island. Our boat and another were moored there. The other boat, let's call it #2, was moored close to the reef, having arrived there first, so ours was tied up at the mooring a bit offshore. We surfaced, identified our boat, and began to swim toward the boarding ladder at its stern.

As soon as we left the lee of the island we felt the current. We were swimming with our faces in the water, and just as we felt the current we spotted our boat's mooring line, stretched taught and actually vibrating in the current. We could see the bottom of the boarding ladder just below the surface, and underneath it the boat's propellers. The propellers were whirling as if the boat were underway, even though the engines were completely shut down, another indication of a rather strong current.

We barely had time to consider what we were seeing, because suddenly we felt like we were swimming upstream. The closer we got to the boat -- and the farther away from land -- the stronger the current. In less than a minute, we were making no headway at all.

We had begun our surface swim side by side, but since I had the bulky camera rig to push along I began to lose ground. I felt myself really beginning to huff and puff with exertion -- not a good sign. We were now less than 3 meters from the boarding ladder, but just couldn't make any headway at all, even though we are both strong swimmers. It was the most frustrating feeling.

Jerry made a few inordinately strong kicks and finally pulled ahead of me. A few more kicks like that and I saw his hand reach out and touch the ladder just as I ran out of steam and began to be swept backwards by the current.

It's funny how, in times like that, all of the training you've had clicks in and behavior switches to automatic. Realizing in a flash that I was not going to make it to the boat and that I was being swept away, I quit fighting the current, deflated my dive vest and dived under the surface. I let the current carry me nearer to boat #2, and I managed to dive deep enough to swim under the vessel. I surfaced again between that boat and the shore, again in the lee where there was no current.

I still had to solve the problem of how to get back to our boat, but at least I was no longer being swept out to sea. I called out and some of the crew of boat #2 looked over the side. I waved my arm. They waved back and hollered hello, thinking, I guess, that I was just being friendly. I called out again, and when a face appeared at the rail, this time I yelled "I need help." This time they listened while I told them about the current, and that I needed to get to our boat.

Meanwhile, Jerry had made it aboard our boat. The crew were below having lunch, and were unaware of what was happening until Jerry came aboard, breathless. His plan was to get out of his heavy gear, and re-enter the water to swim to me with a line that was tied to the boat at one end. The only trouble with that plan was that by the time he climbed on board and looked back, I was gone. He hadn't seen me duck under the surface, and he had no idea that I had managed to dive under the other boat and had made it to the lee side.

Then everything began to happen at once. The crew of boat #2 finally understood my plight. They threw me a line, and literally hauled me alongside and around their bow. They hailed our boat and heaved a line to the crew, ultimately attaching me to that line so that the crew could haul me across.

While that was happening, the next sets of divers in our party surfaced and started to swim toward our boat -- right into the current, of course, and they were as surprised by it as we had been. Jerry and the crew of our boat rushed to set a long 'current line' -- a strong line fastened to the boat's stern at one end, with a float at the other. One by one, the returning divers now swam to the current line, and one by one they got hauled to the boarding ladder.

The current line should have been set as soon as the boat tied up at the mooring. Why it was not was never explained to us. Nevertheless we all made it, camera gear and all. In order to use his arms to swim against the current, one of the divers did have to drop his camera. Fortunately it was attached to him with a lanyard, so he didn't lose it.

Speaking of cameras, when Jerry tells his version of this story, he likes to wait until someone asks what he was thinking when he turned around after boarding the boat and realized I was gone. He always answers, "I was just hoping she hadn't dropped that expensive camera!"

The 'eyes' have it

Awhile back I mentioned that I have a 'thing' for photographing the faces and eyes of creatures in the sea. If you've been following along, you've already seen the conch shell's eyes, and the cross-eyed cone shell. Here are a couple more portraits of critters' eyes.

The creature in the first photo, at right, is a Caribbean Reef Octopus (Octopus briareus). You can click on the photos for a larger view.

In addition to his eyes, take note of his amazing skin. That skin can change from a dark reddish color to the almost iridescent green of the specimen in this photo -- and almost every shade in between. This octopus (like many others) also can change the texture of its skin from smooth to rough in order to blend in with its surroundings.

Finding that octopus was a stroke of luck. The Caribbean Reef Octopus almost always hides in its lair during the day, so the only time a diver is likely to come across one is at night. Indeed, the individual in the photo above was encountered during a night dive at a place called Radar Reef on the north shore of Cayman Brac.

This next eyeball, on the left, belongs to a Blue-spotted Stingray (Taeniura lymma), one of the most easily recognizable of stingray species for obvious reasons. The first time you see one at close range, you can hardly believe your eyes. Those blue spots are quite dazzling.

Blue-spotted Stingrays are quite abundant in the Red Sea. That's where this one was photographed. It was resting on the sand at Ras Mohammed, near the southern tip of the Sinai peninsula. I approached it inch by inch, trying my best not to startle it so that I could get this macro shot of its eye.

This second photo of a Blue-spotted Stingray also was taken in the Red Sea. I'm including it here so that you can have a better idea of what the whole animal looks like.

What's missing from this photo, of course, is the stingray's tail. By the way, yes these animals do have a venomous stinger, but contrary to popular belief, it's not in the end of the tail, and they don't slash their tails around to try to sting prey -- or divers. The stinger -- actually a spine with a barb on the end -- is at the base of the tail.

They're quite shy and often swim away when a diver approaches. They look very pretty when they swim, because they propel themselves through the water by fluttering the edges of their body.

Blue-spotted Stingrays are one of the smaller species of stingray. To give you an idea of their size, the ones in the photos on this page were about one foot (30cm) in diameter.