Monday, December 29, 2008

Sultan Shoal LIghthouse - Sentry of the West

Sultan Shoal Lighthouse used to occupy a strategic location guiding ships from/to the Straits of Malacca into the Western Achorage.

While the island that the lighthouse is sitting has not moved, it is now much closer to the mainland! This is due to the major reclamation works that occurs in Tuas South as well as the creation of the Jurong Island (Jurong Island is linked to the main land by a bridge). From Google Map below, we can see with the extension of Tuas South, it looks like the Lighthouse is now in a "bay"! To the North is Jurong Island and to the West is Tuas South.

The Lighthouse was built on a small outcrop, and to prevent erosion to the shoreline, the island has been ringed with big granite boulders. Thus this island has no mangrove plants, as well as the lack of a sandy shore. However the granite boulders provide good grazing ground and provide good “hold fast” to the grazing shell-animals, especially the Neritae.

Lone Nerite among Mud Creepers

This molluscs come in many colours and sizes, and basically occupies every granite rocks that it was impossible stepping on them as we moved around to explore the organisms that thrive in this area.

On one spot, I foound these 3 Nerites but of different speciesThe whitish spot is actually Nerite's egg capsule. Each of these contains about 30 eggs. Now we know why the whole island is carpeted with Nerites.

Other molluscs that were seen here are the Rock Snail (Family Muricidae) which cling tightly to the wall, Cowrie with length span of about 6 cm. Such beautiful animals will never have the opportunity to grow to this size on the mainland, as it will be collected for its beautiful shells.

Rock Snail (Family Muricidae)

Cowrie (Cypraea arabica). The pattern on the shell looks like Arabic writing, and thus this cowrie is called as such.

Bottom view of the Cowrie

Found in abundance is the Turban Snail, the Turban Snail (Turbo sp) is also a grazer of algae, and its notable characteristics is the “trapdoor”, in some country the operculum is collected and make into buttons. One do not have to wonder why, just look at the beautiful pattern and colour.

Close-up of the shell opening and operculum

The other interesting feature of Sultan Shoal Lighthouse, is a man-made sea water pool, that provides the artificial inter-tidal area that was lacking on this island. In this pool, most of the animals were trapped as the tide receded. Those not considered traps, find this a good refuge, with soft sandy mud, and detritus left by the tide. On this field trip, we have Prof Ng to guide us on crabs.

(Previously Prof Ng guided us in Raffles Lighthouse, where we found the Jaded Pearl Crab)

In this pool, we were able to see many Fiddler Crabs, and Prof Ng pointed out the endangered and beautiful Fiddler Crab (Uca tetragonon).

Fiddler Crab

A pair of Uca tetragonon, male on the left and the female on the right

Usually in the Fiddler (Family Uca), the male is the one that is brightly colour, and the female adorns a duller shade. But not for this species, both the male and female were equally colourful, except that the male has a longer reddish pincer to attract the female as well as to ward off potential male. Uca tetragonon is extremely shy creature, and is very skittish, it will escape to its hole with the slightest disturbance in the form of light, vibration.

Close up of Uca tetragonon (Male)

Close up of Uca tetragonon (Female)

Thus this fiddler seldom strays very far from its nesting holes. Due to its skittishness, Uca tetragonon tends to build their nesting holes near to a wall or rocky outcrop. This also work to our advantage, as to take records of this crab in their undisturbed condition, means one can observe them from above. It is extremely difficult to photo them at ground level, so I climbed onto the pool walls and adopt a prone position from the top (about 4 m up). Fortunately I was using my longer macro lens (Tamron 180 mm – equivalent to 270 mm on the 35 mm scale), even with this focal length, it was not possible to fill the frame with the crabs. A lot of post cropping need to be done, for the images to be blogged!

Overhead shot of Uca tetragonon (Male) near to its nesting hole

Overhead shot of Uca tetragonon (Female) near to its nesting holes feeding on detritus

For survival, these two crabs below have found a novel way of hiding from predators. One has decided to cut a piece of sponge and wrapped around its carapace, and the other has chosen to use a dead leaf as a cover.

From the top, it looks like any piece of “debris”, but below hide this Sponge Crab. Only when it started to move, that it will give itself away.

Top View of the Sponge Crab (Cryptodromia pileifera)

Underside View of the same Sponge Crab (Cryptodromia pileifera)

The other master of camouflage, looks for suitable leaf, and with its modified claws (especially the last pair), it will hold onto suitable size leaf. Once again, until it started to move, especially against the flow of water that it will give itself away.

Notice the last pair of claw of the Leaf Porter Crab (Neodorippe callida)

Another view of the Leaf Porter Crab (Neodorippe callida)

To better understand the Leaf Porter Crab, we decided to give it a different size leaf, and somehow it find our leaf was less than ideal, and will always stick to its own! My conclusion is that the size and span of its claws must match the holding areas of the leaf, otherwise it will not be able to use the leaf effectively!

Leaf must fit to the size of its holding claws

Another specimen that was discovered by Prof Ng, was this Pseudoscorpion (Parahya submersa). It was small, and made me wonder how he managed to find it in the first place. For comparison, look at the grains of sand, in fact our estimation is that its body is only about 3 mm long. Not much is written about this marine Pseudoscorpion, and literature search on the web did not yield any interesting results!

Compare the grain of sands to the Pseudoscorpion

Blow-up image of the Pseudoscorpion

(In macro photography and depending on the lens, the distance between the lens and the object is 12 to 15 cm. Handholding and expecting to get sharp details requires very good hand holdin and breathing skill. But one technique that I find useful, is to fire rapid shot by setting the camera to continuous shooting mode, and having pre-focused (auto focus for macro is not going to work), take a number of shots. Manage to get one decent shot from about 25 shots. If you happen to be involved in excessive menial tasks before the picture taking, you will find that most of your shots will be ruined by your shaking hands!)

For other findings on this field trip, please check out

Where Discovery Begins

Manta Blog


God's Wonderful Creation

Monday, November 3, 2008

Autumn Colour - Preservation of Life

The colourful leaves that we see in the Autumn is a result of a process whereby Deciduous trees prepared for the wintery weather, when there is less water, cold spell and lack of sunlight.

Similar to other organism, preparation for winter is most vital for their survival. Other animals migrate, and some started the process of hibernation. But for plant, which is not warm blooded, the plant has to prepare for winter in a special plant way!
The process of preparation for Winter is called Hardening, and there are 3 stages as to how trees prepared for the winter. But the method and preparation varies from species to species and are program into each of these species.

Stage 1 – Dropping of Leaves
Prior to the leaves being shed from the trees, it will have undergone a most beautiful process of colour change. To understand this transformation, it is important to go micro and understand the various cellular structure and the synthesizing of metabolic materials in the plant.

In a typical leaves, there are plastids (plant cells that are responsible for energy creation and storage). The most common plastid will be the Chloroplast that enables the plant to photosynthesis from the sun ray to create starch out of carbon dioxide. In these plastids, they contains various pigments which give rise to the myriads of colours found on leaves, the pigment in different percentage will give rise to the colour of the leaves in the various seasons.

Chlorophyll - Repsonsible for the green colours that we see on leaves, and vital for leaves to be able to photosynthesis.. This pigment absorbs the Red and Blue colours and reflect the Green. The molecular structure of chlorophyll is large (C55H70MgN4O6). Chlorophyll attached itself around the chloroplast or the chloroplast is a plastid that contains the chlorophyll. Chlorophyll is not a stable product and tends to break down under intense sunlight, and has to be continuously regenerated by the plant where light, warm temperature and water are present.

Caroteneoid - this pigment absorbs the blue and blue-green light, and is responsible for the orange colour that we see on the leaves. This pigment is also found in fruit and roots like corns and carrot. Similar to chlorophyll, the molecule is large (C40H36) but more stable than chlorophyll which gives the orangey hue to the leaves when the chlorophyll is depleted from the leaves. The carotene pigment is found in the in another type plastid called the Chromoplast.

Xanthophyll - belonging to the carotenoids group, and is responsible for the yellow colour commonly seen in autumn leaf.

Anthocyanin - unlike the above pigmentation that is being held in plastids, anthocyanin are found in the plant sap. Anthocyanin absorbs the blue, blue-green and green colours of light, and thus give the appearance of red and purple. This pigment is commonly found in fruits, giving rise to the familiar redness in apple and the purplishness in grape. The colouration of anthocyanin is very much depends on the concentration of the sap and sunlight. The stronger the light, the stronger will be the reaction. Which will explain, why apple can exhibit different colouration from dark red to light red and even green. Anthocyanin is a very strong anti-oxidant, and is extremely beneficial to us, and therefore when eating fruits, do not peel the skin away. Give it a good wash.

As winter approaches, the weather become colder, daylight is shorter, and water becomes scarce. These conditions lead to the plant hardening process of retracting and storing the food (carbohydrate) in the roots. At the same time, the leaf stalk started to swell which will restrict nutrient going to the leaf. Glucose and waste are now trapped in the leaves, and without nutrient and water, the chlorophyll diminishes and eventually disappears. With the absence of chlorophyll, the other two pigment becomes more apparent. The colours presentation will be due to the different percentage of the carotenoid and anthocyanin pigment that are left behind in the leaves.

Eventually, the leaves will drop from the tree. Now the tree is hardened for winter, and is capable of managing winter with temperature dropping to -10 deg C.

Step 2 – Further hardening of Trees
If the temperature started to drop further, and hopefully in a gradual manner, trees will have ample time to further harden itself by migrating the sap from the cell structure into the inter-cellular space. Tree sap has long molecular structure, and with long molecular structure, the tree sap has lower freezing point (called it a type of anti-freeze). However, occasionally with sudden freezing spell, trees that do not have the opportunity to harden will suffer from the freeze, and at times parts of the trees will be damaged.

The last stage which is still unknown to scientist is the transformation of ice crystal in the cell, from sharp crystal to rounded edge crystal. With this transformation, the cell will not be damaged.

Through this complicated process of hardening for winter, we can enjoy and be bewildered at the beautiful fall foliage. The deciduous trees are now ready to “hibernate” for the winter to present itself once again in its full glory in spring. But this time it will be the flowers that will paint the scenery.

All pictures taken at West Bloomfield, Michigan, US.

Based on the principle of Chlorophyll being responsible for the green we see in tropic Singapore, we will occasionally come across autumn foliage in some of our trees (namely trees like the Sea Almond Terminalia catappa and Blind-Your-Eyes Exoecaria agallocha). During a long dry spell, the trees in self preservation will restrict water flow to the leaves, and without the water, the leaves will lose its chlorophyll and start to change its primary green colour.

With this knowledge, now one can look and be bewildered by the beautiful fall colours and fathom the processes that have gone into this transformation.

Thursday, October 30, 2008

Along Clementi "River" (Holland Woods)

Along Clementi Road, opposite Ngee Ann Polytechnic there is this Strom Drain which in Singapore size, looks like a river.
(Also known as Holland Woods)

I have always wanted to explore this area, and on Deepavali, it was a good opportunity as I need the sunlight to help me recover from jet lag, as I have just returned from the US.

The first activity that caught our eyes was this "fisherman", as can be seen from the picture, there are nets in the water by evidence of the styrofoam float. What fish dwell in this place, probably tilapia. But we did not hang around to find out.

With such expanse of water, one can definitely find the super agile dragonfly skirting the waterlines. Though look like 2 different species, but actually they are ONE. The Red is the Male and the Yelllow - the female Asian Scarlet Dragonfly (Crocothemis servilia)

Walking along the bank of this "river", I chanced for the second time on a lonesome Hoverfly (Family Syrphidae). Such fly is characterised by its big bulging eyes and short antennae.

For protection, it has acquired pattern to that of wasp (Batesian mimics). The belly of the Hoverfly has striped pattern similar to the wasp. But when it comes to rest, its outline is that of a fly! But some Hoverfly has "waist"to further confuse its predator.

The Hoverfly is a friend to the gardeners, as its larvae feeds on aphids.

Usually the male Hoverfly will hover on certain spot in space to attract female, and will defend this piece of 3 dimension space against other intruders that dare to encroach into its airspace.

Having to hover demand alot of energy, and occasionally the Hoverfly will have to "re-fuel" by drinking nectars from nearby flowers.

Below is a picture of a housefly, and in this condition, this housefly looks pretty nice!

There were much vegetation, and reaching the railway line, we came across this 7 Golden Candle stick (Cassia alata), with beautiful bulge and patterns, and was frequented by ants.

We have to visit this place again, especially in the morning for we have heard many birds call, and managed to catch glances as they flew off. This brown bird that flew off is a very rare Black Bittern (Dupetor flavicollis). Unfortunately I was not able to get a ground shot as we startled it when it was foraging in the marshy drain.
It has been certainly a surprise location, as this place is sandwiched between busy Clementi and Bukit Timah. Certainly we will be making another reconaissance again.

Sunday, August 3, 2008

A Crab with no name on Satumu

Pulau Satumu
The most Southern Part of Terra Firma in Singapore territory. Or more commonly known as Raffles Lighthouse.

Once again we were indeed grateful for the permission granted to us to do an exploratory intertidal walk on Pulau Satumu which is a restricted area.

Previously when we did our intertidal walk, we managed to see many Criniods (Feather Stars) in different colours. However, this time - the marked difference that I noticed was the numerous Nerites (Snails) that were on every rocks that we walked, and the other was the Sargassum (Family Sargassaceae) that has covered much of the intertidal areas.

Sargassum coverecd Inter-tidal areas
Nerite scavenging for foods on the rocks.

Stranded in some pocket of water, we found these two False Clown Fish (Amphiprion ocellaris), near to this pocket of water was another pocket with a Sea Anemone. Apparently, they must have strayed and landed themselves from their host. Well the next tide will bring a sweet union to these dual.

While scouting around, I chanced uon this "split" coral. I have read that as coral grows, the individual polyp will raise its base plate (which is the bottom of the coral cell), and start to build the calcium wall around it. But that is from book, now from the "split" coral, I was able to see the formation of the individual walls of each of these polyps.

Why did the coral split? It does not look like a mechanical damage, but somehow it showed that two sides of the corals decided to go their separate ways!

Any Coral experts, maybe you can enlighten me on this unusual sighting.

Refer to Ria's reply below. This is a Zoanthid, my hand must be numbed on that day, as I touch the split zone and felt that it was hard. Thanks to Ria for the correction.

On this trip, we have the priviledge of two Crab Experts in our group. We were told to look for a special crab. The instructions given were

  • It has a squarish carapace
  • It has greenish dots on its carapace
  • It dislikes water, and tend to be above the water line
  • It dwells behind rocks and boulders

The uniqueness of this crab is that it has yet to be ID, and thus has no names (scientifically or common). Its cousins have been seen in Indonesia, Taiwan and Japan, except that in Taiwan it has blusih dots instead of the greenish dots.

With these instructions, we went a hunting - alas, we were bad hunters and found none. But the expert managed to land one, and we managed to take a lot of closed-up shots of this female "model".

It has lost one leg, and we were told that crabs have certain set of muscles near to the body. Upon being threatened, they can constrict this muscles such that the legs can just dislodge itself. Possibly just like the lizard's tail whereby losing a limb (which can grow back in the next moult) is more beneficial than being eaten up.

Upper picture taken, showing the almost squarish carapace with yellowish-greenish dots.
Frontal Shots of this lady

Closed-Up of the "face
Close up of the eye - notice that there is a protrusion on the eye. This is like a hair on the eye.

Underside of this female unknown ID crab with its orange claws.

Till the ID of this crab is published, I think I am at liberty to call this crab "Jaded Pearls" Crab.
Jade tends to be green, and the dots are like pearl. So Jaded Pearls Crab in this blog.

The next time to Satumu, I will be looking up for more Jade!