justin dive adventures

Sunday, March 16, 2008

Toddycats' first labrador walk

On 8th March 2008, toddycats conducted a walk at Labrador Park for its members.. I had the privilage to be the guide for the group from NUS-SPS(Special program in Science).

The walk was scheduled to start at 4pm. However, the over enthusiasm of the SPS group caused them to arrived extremely early, at 3:15pm, and waiting at the designated meeting place. As such, they had to wait for their guide who, oblivious to them, slipped into their midst when he arrived at 3:30pm!

However, at 4pm, other than this group of people, no one else was around! Deep in my mind, I was concerned: Was no one else turning up? Then I called Siva, but he did not pick up the phone! Oh no!... Until I heard news from one of the other participants...

In fact, the rest of the participants were gathering and waitng at the entrance of the park, and eating ice-cream with Siva! It was only at around 4:30pm that they slowly strolled to the designated meeting point...

The walk proceed as expected since then.... I was unable to take any pictures on that day as I was busy guiding. However, my enthusiastic group contributed the following pictures..

Sunday, March 9, 2008

Love is in the sea...

On 9th March 2008, the group 'Hermit Crab' consisting of 7 participants and 2 guides visited the Semakau Landfill with the Raffles Museum of Biodiversity Research for Nature Walks. The main guide was Ka Ching and her assistant: Justin.

When we first arrived on the island, it was raining cat and dogs, which was a disappointment for many of us as our walks are very rain dependent. However, it stopped right before the Semakau tour began.

Landfill tours

Participants were first introduced by the NEA guide to the operations of the landfill through a bus ride along the man-made bun which surrounds the site. Along the way, they were introduced to the marine-transfer-station where participants had opportunity to smell the incinerated waste to be deposited on the landfills. Next, they were shown the landfills cells while travelling along the man-made buns to the southern-most point of the landfill, which is also the southern-most point at which the public can access. There, the participants alight for picture taking.

Next, the bus brought the group to the entrance of the secondary coastal forest which grows on the actual Pulau Semakau. There, the group tracked along the water-logged footpath to the intertidal areas of the island, where the shore tours began, incidentally with strong theme of love..

Arrival at the shores

First, participants were briefly explained by Ka Ching to intertidal zone of the shores. Hence, emphasis was on the need for adaptions of the creatures found there due to the harsh conditions caused by tidal change. Thereafter, they were introduced to the first animal on the shore - OYSTERS.

Love Choice of female Fiddler

Next, the group were led to the small mangrove patch where they were introduced to the plant and its community. Examples include the stilt root and vivipary of the Rhizophora plant, the anaerobic conditions of the soil and most captivating, the love life of the fiddler crabs.

The male of the fiddler crabs has one of its claws abnormally enlarged. With this cumbersome large claw, the male feeding and movement ability is compromised. On top of that, their large claws make them easier to be spotted by predators and to some extent, decrease their survival chances. Hence the question was: Why then does male fiddler crabs have one abnormally large claws if it is so disadvantage to them? The answer is in LOVE...

Biologically speaking, this is called sexual selection, where in this case, the female fiddler crabs have a "WEIRD" preferences to mate with males with one abnormally large claws. Hence the results: Male offspring also have one large claws. Thus, this traits are passed on to subsequent generations. Males with claws which are both normal sized will therefore not be able to find mate and hence not able to reproduce. (Note: Love lesson no. 1 from nature: Love may not always be logical)

Possessive love story of Common Sea star

After that, the "Hermit Crabs" were shown the Common Sea Stars. On top of their distinct tube feet and camouflaging colouration, the next love story was told here - How to stake claim on your mate.

When the sea stars are about to mate, the smaller male will stack on top of the female in order to 'stake its claim' on the female (Picture can be found at this link). However, their sexual organs are not in contact with each other. Hence for successful mating, both the eggs and sperms were released in synchrony for fertilisation to occur externally! A very unique way of making babies.....

Bisexual?

The next love story told was from the world of hermaphrodites, with examples from some species of flatworms and nudibranch. As it requires more investments to be the female in reproduction, some of these hermaphrodites species will literally duel to be the male in the courtship! Each of them will attempt to stab their penis into an exposed area of its sex partner's body while avoiding getting jabbed itself. In some cases, they even attempt to cut off each other's penis (termed penis fencing)!! In the end, the loser of this mating duel will be the female...

Eggs of mollusks

As the group ventured further seaward, products of reproductions were spotted... Eggs... From the phylum mollusa. Strings of snail eggs were spotted. Also, the group had the privilege of watching a 'nature slow delivery' of Noble Volute (2nd picture below) laying eggs! Seeing the group's strong interest in reproduction, when a nerite was explained to them, Justin took the opportunity to show the group on how the nerites mate(Picture far below, not from the walk)

Conclusion

Therefore, the walk for the 'hermit crabs' do indeed contain essence of "Love in the sea". And its atmosphere was made more apparent under the romantic sunset backdrop of Pulau Semakau....

Pictures of some of the 'hermit crab':

__________________________________________________________________

Other organisms featured on the tour:

Fan Worm

Assortment of Sea cucumbers

Knobby Cake Sea Star

Octopus

Keywords:

sexual selection: A form of natural selection in which, according to Darwin's theory, the male or female is attracted by certain characteristics, form, colour, behaviour, etc., in the opposite sex; thus modifications of a special nature are brought about in the species.

hermaphrodite: animal having both male female reproductive organs

mollusks: A phylum of coelomate protosome animals characteristized by a soft body, viseral mass, mantle, and foot

References:

Definition: Sexual selection from Online Medical Dictionary (2000).University of Newcastle upon Tyne-The Centre for Cancer Education. Retrieved 23:00, March 10, 2008, from http://cancerweb.ncl.ac.uk/cgi-bin/omd?sexual+selection

Peter K.L. Ng, Shirley S.L. Lim, Wang Luan-Keng, Leo W.H. Tan.(2007) Private Lives, An Expose of Singapore's Shores. The Raffles Museum of Biodiversity Research. Department of Biological Sciences, National University of Singapore.

WordNet Search - 3.0: hermaphrodite. (2006). Cognitive Science Laboratory,Princeton University. Retrieved 23:00, March 10, 2008, from
http://wordnet.princeton.edu/perl/webwn?s=hermaphrodite

S. Milius (1998) 'Hermaphrodites duel for manhood'. Science News Online. Retrieved 23:00, March 10, 2008, from

http://sciencenewsmagazine.org/pages/sn_arc98/2_14_98/fob2.htm

Solomon, Berg and Martin. (2008) Biology, 8th Edition. Thomson Brooks/Cole.

Sunday, January 13, 2008

'Longkang habitat' in Pulau Ubin

During the earlier days, when kampongs were still a common sight on mainland Singapore, 'longkangs' were playgrounds to the now-grown-up kids. They would catch fishs such as bettas (most people know it as 'fighting fish') to rear them and subsequently used them to fight with their friends' bettas.

Also, it was also a place of owners to release fishes and other animals 'back to their nature'. Some of these released animals were not native in our region. Over time, a community of both native and invasive species is created within the longkang, eventually forming a longkang habitat.........

Recently, while walking along a road in Pulau Ubin with KS, RY, JL and IV, we chanced upon a longkang which was teaming with life. With one glance, we saw animals from 2 phylums and about 5 classes, mainly from the subphylum Vetebrata which is under phylum Chordata.

Apparently, like other longkangs, there were some invasive species, for example the tortise (class reptilia), which we could not take pictures of due to reflection of the water. Also, this fish (identification unknown) may not be a native as well.

Schools of what looked like small half-beaks were also seen as well (picture below).

As this longkang is in close proximity to a mangrove habitat, some of the mangrove species were also seen, mainly the gobies..

Also, a tree climbing crab (Episesarma sp.)was spotted by KS at the edge of the longkang (picture above). Some small mudlobster mounds (no picture) and burrows (picture below) were seen around the longkang as well. Species from the subphylum Crustacea (refer to the Spiders at our backyard..) seems to have a foothold here as well.

Couldn't resist the temptation, I decided to enter the longkang(picture below) to 'be 1 with the habitat' as well while the rest remained on the road to watch from a distance (picture far below). There, I tasted the water as well to confirm that it was fresh water.

However, time passed quite quickly and we had to move on. Reluctantly, I had to leave the longkang, bringing nothing but pictures and an experience which not many urban dwellers have in our air-conditioned nation....

Note: scientifically, there is no such term as longkang habitat.

Translation:

longkang ==> drain

Keywords:

Vetebrate: chordates which has a backbone, or vertebral column, that forms the skeletal axis of the body.

Chordates: Deuterostome animals that, at some time in their lives, have a cartilaginous, dorsal skeletal structure called a notochord; a dorsal, tubular, nerve cord; pharyngeal gill grooves; and a postanal tail.

Also featured in:

Relaxing Ubin exploration (Part I)

References:

Solomon, Berg and Martin. (2008) Biology, 8th Edition. Thomson Brooks/Cole.

Peter K L Ng and N Sivasothi. (1999) "A Guide to the Mangroves of Singapore II: Animal Diversity". Singapore Science Centre.

Tuesday, January 8, 2008

Labrador Episode 4: A New Hope

A short time ago in the beach far away......

It is a period of debris. bloggers, writing from a hiden base, have won their first victory against the destruction to the intertidals of Labrador.

During the visit, blogger managed to take pictures of the remnant of the threat's ultimate structure, the CON-CRETE, a foreign object with enough power to destroy an entire area beneath it.

Persued with the extreme excitment, Justin races home abroad his car, custodian of the remainder concretes that can save the habitat and restore life to the beach of Labrador....

Thus... A NEW HOPE.....

Scenes from previous episodes:

Synoposis for next Episode: Return of the Labrador...
when these are removed...

Other Versions:

Under protection?

Credits:

Updates on large concrete slabs on Labrador shore

Note: abstract edited from the opening of Starwars episode 4.

Sunday, December 30, 2007

Open up your eyes to the beach..

Some of us may say that the beaches of Singapore are almost dead. This may be true, if we have a quick glance on the beach, seeing nothing but sand and rocks.

Well, look again... The first picture is that of a sole fish and the second is that of a sandstar, Astropecten sp. The 'stone' is in fact a ball sea cucumber! Heres the more obvious pictures..

These are the form of protection mechanism by these creatures by avoiding detection with their colouration. As such, we may not be able to spot them easily... But by going to the beaches with an open mind, who knows what else can be spotted.. On the Changi beach on mainland Siungapore... Kids??
Noo... These kids were excited by the sight of solefish and attempting to follow it... So, these are some of what you can see on the beach...

Note: The above bivalve was alive and flapping its shell when held on hand..

More information on Changi beach can be found on:

Wonderful Creation blog

Thursday, December 20, 2007

Spiders at our backyard..

I was invited by the 'Most Naked Hermit Crab' for a walk at Kranji Trail/Sungei Buloh Nature Reserve on morning of 15 December 2007. There were 7 of us present for the walk which started from Kranji Reservoir.

During the walk, whenever someone spotted something interesting, everyone would bring up their cameras, snapping pictures of the creatures (the following picture from left: JL, JH, SY, RY).

However, my focus was on spiders, which belongs to the Subphylum Chelicerata under the Phylum Arthropoda. Horseshoe crabs, the only surviving merostomes, are also classified under the same subphylum, which accounts for the well-said phrase- 'Horseshoe crab is more related to spiders than crabs'. Marine creatures such as lobsters, crabs and shrimp shares the same phylum as spiders althougth they belong to the Subphylum Crustacea.

Hence, my quest was to look out for spider and webs throughout the walk.

My first observations was on the different types of webs they build. I noticed that some spiders build orb-shaped webs, while some build tent-shaped webs(picture unavailable) and some don't build webs at all.

One example of a non-web builder is the 'crab spider' which ambushes preys instead of trapping them, which we commonly know. However, they are not active hunters. Instead, they camouflage among flowers with their body coloration in wait for unsuspecting preys before graping them with their front appendages. As the name suggests, these spiders are recognised by their resemblence to crabs with their 1st 2 pairs of legs held in a wide position resembling the claw-appendages of crabs.

Another active hunter found was the Fighting Spider (Thiania bhamoensis). It has the ability to jump around with its muscular legs. However, these spiders do builds tent-shaped webs for protection purposes, such as storing their eggs, instead of prey trapping. While we were taking pictures of it, the spiders was 'jumping from one camera to another- RY' because of its curious nature.

As for prey-trapping spiders, I had the privilage of observing a live action of a orb-web spider (Brown sailor spider, Neoscona nautica) trapping its prey. As I was taking picture of the spider, it suddenly scurried to the lower region of web where a small struggling insect was trapped. The spider was observed what seemed like wrapping the prey with silk (other processes may happen as well, though not observed). In less than a minute, the prey was fully wrapped and became completely motionless before the spider moved back to its orginal position on the web.

Brown sailor spider (top: before prey got trapped, bottom: prey fully wrapped by the spider)

On top of that, we spotted a few other species of orb-web spiders, mainly the Oval St Andrew's Cross Spider (Argiope aemula) and Hasselt's Spiny Spider (Gasteracantha hasseltii).

Oval St Andrew's Cross Spider (top) and Hasselt's Spiny Spider (bottom).

Also, in the mangrove area, we saw this spider with a huge white sac beneath its body, probably a egg sac. As suggested by SY 's friend, it might be a huntsman spider (family Sparassidae).

As spiders have hard exoskeletons, in order for their size to increase, moulting must occur, just like crustaceans. Along the Kranji Trail, I managed to spot one of the shedded exoskeleton of an unknown species of spider.

We were fortunate the rain came only after the walk. All in all, although tired, each of us managed to bring back many photo memories of the pieces of nature in Singapore. And for me, specifically the relatives of crustaceans.....

Keywords:

Arthropod (ar'throh-pod): An invertebrate that belongs to phylum Arthropoda: characterized by a hard exoskeleton; a segmented body; and paired, jointed appendages.

Exoskeleton (ex" oh-skel'eh-ton): An external skeleton, such as the shell of mollusks or outer covering of arthropods; provides protection and sites of attachment for muscles.

References:
Solomon, Berg and Martin. (2008) Biology, 8th Edition. Thomson Brooks/Cole.

Peter K L Ng and N Sivasothi. (1999) "A Guide to the Mangroves of Singapore II: Animal Diversity". Singapore Science Centre.

Joseph K H Koh. (1989) "A Guide to Common Singapore Spiders", BP Guides, Science Centre.

Note:

Initially planned an entry covering on Pasir Ris Mangrove on 'Playing Death.. to stay alive' before this. However, regretfully, the pictures were all accidently deleted from my computer, hence abandoning that entry.