Pulau Sipadan: The Story So Far

Pulau Sipadan- Jewel of the Celebes Sea

It has amazed thousands of visitors around the world with its serene coral reefs and profusion of marine biodiversity beyond imagination ever since renowned aquatic explorer,

Jacques Cousteau first penetrated into its depths in awe and wonder that is reflected in his well-versed quote- "I have seen no other places like Sipadan, 45 years ago, but now no more. Now we have found an untouched piece of art" during his expedition across the Sulu-Celebes Sea. Superlative descriptions have been a common "trademark" for Pulau Sipadan. Everyone who have visited this 12 hectares island carry their own accounts of adventures, each as amazing as the other. However, underlying all these colourful stories is one that many have not ventured into yet, a story that is as grand as its coral reefs - The Story of the Evolution of Pulau Sipadan into the island we know today.

Semporna town near Pulau Sipadan. The flatland across the shallow strait is Pulau Bum Bum and the tall imposing peaks behind it is Pulau Gaya and Pulau Boheydulang.

Beyond the acknowledgement of Pulau Sipadan as a oceanic, volcanic sea mount in tourists brochures, little else about its origin is mentioned. So, to fill this information gap that some visitors (including me) may wonder about, I've done a small online research to analyse and share this particular island's history with everyone. The following may not be a complete description of the island's formation but nevertheless, it sheds some light to this legendary island's origins.

To fully understand the geological history of Pulau Sipadan, we have to look at the bigger picture that is Sabah, the continental tip of Northern Borneo. Turning the clock back to more than 65 million years ago, much of North Borneo was submerged under deep waters. As the Tertiary period (65 million - 2.588 million years ago) begins, the first lands can be seen breaking the cerulean waters in the form of a chain of islands that resembles much more of a growing underwater mountain range of what is now the tallest in Borneo- the Crocker Range. As time progresses, clouds bringing storms and rains washed the slopes of these majestic mountain-islands, thus distributing alluvial deposits along the coast until these islands became linked.

Mount Kinabalu, at 4095m, is the tallest peak in Crocker Range at present day.

Kinabatangan Delta of present day Borneo gives us a glimpse of what Central Borneo used to be like.

The Eurasian Plate is where the Sundaland (the shallow, light blue area) is. The Philippine plate can be seen as a dark (deep) area off Northeastern Borneo.

The movement of Philippine plate against the Eurasian plate north of Sabah further pushes the mountain range higher and higher while creating a wide floodplain to the east with soil runoff from the highlands during the Miocene period (23.03 - 5.33 million years ago). Meanwhile, the same Philippine plate in the southeastern end of North Borneo starts to drift apart from the Eurasian "mainland", causing a rift and sets off the red hot lava bursting out of the cracked Earth crust from the deep magma below. Soon, the deep seas off the developing floodplains east of Crocker Range (now Central Sabah) were boiling hot with lava and pumice bursting out of the surface all the time. This will soon form most of Eastern Sabah, in which the Semporna Peninsula will emerge from the thick clouds of volcanic ashes.

Remains of ancient volcanoes in Tawau, west of Semporna.

Volcanic rocks of Tawau indicates the region was once highly active in volcanic activity.

Low tides exposes ancient volcanic pumice and rock deposits (dark brown areas) along mainland Semporna and Pulau Bum Bum.

Across the 100m tall developing volcanic cones along Semporna Peninsula, ashes spews and radiate out into the ocean and the ancient floodplains of Central Sabah, joining nearby islands and expanding its landmass. However, further out in the deep ocean off the edge of Eurasian Plate, an undersea volcano far removed from the bustling volcanic activity miles from it, silently build in height. Forwarding the frame in a year per second, one would see steam rising out from the deep Celebes Sea and then, a dark mass of rock and pumice pops out of the surface and extends in width and height. Pulau Sipadan is born. Since it is separated from mainland Semporna by deep waters, the lowland sediments of Semporna never made it to Sipadan.

Volcanic rocks exposed on Pulau Menampilik off Semporna.

The chain of islands off Southeastern Semporna with prominent exposed volcanic rocks.

Sometime later, the lava flows and plumes disappeared and volcanoes silenced. Clumps of greenery previously existed only in areas of least volcanic activity flourished and spreaded across the landscape. Gradually, the dark rocks of past ages got smothered in rainforests and mangroves, only occasionally protruding as hardened lava cones at higher peaks. Ashes not covered by vegetation end up being washed away by rains and wave action of the sea. As time progresses, the ice age of the Holocene (approximately 12000 years ago) arrives. As if a plug in a basin of seawater is being pulled, sea levels bordering the peninsula dramatically retreated 120m below sea level. Thus, "raising" the badly worn volcanic peaks of Semporna some 100m above that era's shoreline. Across the narrow band of water, Sipadan stood as a lonely, weathered and extinct volcano draped in lush forests on its slopes and coastal grasslands along it's coasts. During this time, some ancient fauna and flora might have migrated to the island through the deep but short passage of sea. There may be corals fringing the ancient coast as well.

Fertile soils encourage rapid growth of rainforests across the volcanic slopes of the mountains on mainland Semporna.

Manado Tua of North Sulawesi, Indonesia. Pulau Sipadan was once similar in appearance to this island when it was a volcanic mountain island many millenia ago.

Bukit Tengkorak with a volcanic outcrop, near Semporna town. The sign of an ancient volcanic land.

Fertile lands on the southeastern tip of Semporna Peninsula is the testimony of the volcanoes around the area.

Corals are the building blocks of Sipadan's limestone.

Approaching 6000 years before present day, the ending of ice age marked another dramatic event- the increase in sea level or mass-flooding. Once again, lowlands shrinked and forests of the past disappeared below the waves. The seawater soon reached present day levels at 6070 years before present, only to exceed another tenths of metres of height for the following millenia. Thus, the cone became completely submerged. Corals started to form at the top most part of the seamount, growing outwards slightly below sea level. Before long, the sea levels retreated again, exposing the limestone reefs to the atmosphere and creating habitat for forest recolonisation. During this period of emergence, parts of the limestone eroded to form a complex cave system complete with stalactites and stalagmites which will be known as the Turtles' Tomb or Cave due to the high numbers of unfortunate turtles trapped and died in the labyrinths of this cave. What happens next will define Sipadan's present day characteristics.

Coral-fringe islands is now part of Semporna's modern feature after the sea level rise.

The island chain in the foreground used to be high and dry with grasslands dominating valleys between them and the sea as well as mainland Semporna (background).

During the exposure of limestone, this may be what Sipadan looked like. Picture taken in Nusa Penida, Bali, Indonesia, an island made of raised coral limestone.

The submerged cave entrance to Turtle's Tomb.

Crevices like these may be the access routes to caves lying deep inside Sipadan limestone.

Being on a mobile, active edge of the Philippine plate, it so happened that Sipadan slides along the growing tectonic plate and the limestone forest began to submerged again, probably eliminating the terrestrial ecosystem all together. Then, polyps of modern corals settled on the ready-made reefs of craggy limestone to expand as a reef and form the strange shape of a "mushroom" along the top perimeter of the seamount. Up above water, the reefs slowly give way to a sand bank which accumulates and grows as time passes. Birds and storms bring driftwood, sea beans, plants and animals to colonise the sandy island. Finally, the ecosystem of coastal forests and coral reefs reached their climax that is Pulau Sipadan today.

The sand bar formed near Semporna show what modern Sipadan was like in the initial stages of development.

As sand accumulates, the land mass increases and vegetation flourishes as shown here in Pulau Mabul, near Sipadan.

Driftwood washed up by storms brings in many flora and fauna from nearby terrestrial ecosystems.

The product of millenia of colonisation by terrestrial flora and fauna- the dense coastal forest of Pulau Sipadan.

The famous vertical drop off of Sipadan. Could this be the upper part of the "mushroom" structure?

Diving along the ancient limestone cliff.

Sipadan today as seen from above (Google Earth).

Indeed, Pulau Sipadan has gone a long way since becoming a little lava-spewing bump at the edge of the Philippine Shelf and Eurasian Plate to the grandeur of today. Not surprisingly, the story of this tiny island in the Celebes Sea does not end here. Maybe Sipadan is going to expand its landmass? Or rather swept below the waves by climate change induced sea level rise? Or, as some joked, topple over into the abyss of the Celebes due to excessive pressure on the seamount by the "mushroom" coral limestone? (Note: The last theory is mend to be, well, a joke!)

Reference:
1.Charles S. Hutchison, 2006 The Unique Geology of Sabah (North Borneo). University of Malaya, Kuala Lumpur. (click here)

2. JED Fox. General Geology of Sabah (excerpt). Sabah Forestry Department. (click here)

3.Intercoastal Zone Management Project, 1998. Sabah Coastal Zone Profile. Town & Regional Planning Department Sabah. (click here)

4.Allagu Ballaguru and Gary Nichols, 2003. Tertiary stratigraphy and basin evolution, southern Sabah (Malaysian Borneo). Journal of Asian Earth Sciences V. 23, Iss. 4: 537-554

5.Mohd Harun Abdullah, Mazlin B. Mokhtar, Sanudin Hj. Tahir and Almah Bt.
Awaluddin, 1997. Do Tides Affect Water Quality in the Upper Phreatic Zone of a Small Oceanic Island – Sipadan Island, Malaysia? Environmental Geology 29(1/2):112-117

6.Ahmad Zaharin Aris, Mohd Harun Abdullah, Kim Kyoung Woong, 2006. Hydrochemical Analysis on seawater intrusion of small carbonate islands: Manukan and Sipadan, Sabah. Proceedings of the 2nd Southeast Asian Natural resources and Environmental Management Conference, kota Kinabalu, Nov. 21-23, 2006, pp.40-44

Gua Naga Mas: The Golden Dragon of Kinta Valley

Nestled atop a typical creeper-draped hill on the side of the busy North-South Highway is a hidden cave with a secret that would entice anyone who stumbles upon it......

Gunung Pua's densely vegetated peak.

As our group (a motley crew of nature lovers and adventure seekers) turned around a strangely silent and empty road with cow manure scattered across it in an industrial park, a small limestone outcrop emerges from behind the metal roof of a warehouse - Gunung Pua (Pua Mountain, which actually is more like a hill) is just a hundred metres away. We pulled into a sandy, uneven road flanked by grass and shrubs typical of Kinta Valley's post-tin mining terrain. A few bumps and splashes of water and we have reached the foot of this forest clad hill. Creepers droop down from the cliffs, blanketing their rugged features from view. Peculiarly low trees and shrubs with patches of bamboo colonies occupy the upper reaches of the outcrop. Perhaps they are signs of human disturbances or forest fires sometime ago?

Trekking up the steps towards the cave.

Our guide made a headway by slashing the undergrowth that covered much of the path leading up to the cave. Rocks have been placed in a manner that resembles a staircase along the steep cliffs. It must have not been used for ages. But who built it? What's the purpose of it? Taking my mind off that matter for a moment, I scanned the boulders and strange rocky features for rare and endemic plants and wildlife.

This herb with blue fowers must be a limestone-endemic.

The peculiar leaf of another plant.

This palm is probably rare and endemic to limestone forests of Kinta Valley.

A cluster of plants with elongated leaves and bluish flowers attracted our attention. Further up the cliff, a large palm and another peculiar plant with paw shaped leaves adorns the understory section of this forest. They must be rare limestone-loving plants, found only on this hill and probably the nearby ones.

A strange yet beautiful rock formation.

Results from a small packet of soil sample shows plenty of small snails including Rhiostoma jousseaumei , Alycaeus perakensis, Discartemon leptoglyphus, Georissa monterosatiana, Philalanka sp., Diplommatina nevilli, Allopeas clavulinum, Opisthostoma megalomphalum etc.

Mosses covered most of the exposed limestone with one little outcrop having flaky, vein-like protrusions across the surfacing reminiscent of Salvador Dali's surrealistic sculptures. There were visibly no large snails around, so I proceeded with collecting a bagfull of dirt at the base of the rockface for microsnail examination back at my "home-lab". We continue up a forest clearing with regenerating shrubs. Before long, the path's bushes gave way to rock and dirt. Looking up, large stalactites encrusted with green algae hangs from a wet, carved rock ceilling above. We've reached Gua Naga Mas which literally translates as Golden Dragon Cave in Malay. Guano spread across the floor into the dark end of the cave chamber where a flight of algae-green, slippery stairs leads to a long abandoned Chinese temple. According to the book "Kinta Valley: Pioneering Malaysia's Modern Development" by Khoo Salma Nasution & Abdur-Razzaq Lubis, this temple and the stairs seen earlier was built in the 1800(?) when the valley below (known as Tekkah) was a hotbed for tin mining activity by the Chinese. A tin economy slump soon brought the industry to its knees and thus, workers abandoned the area including this cave temple. This makes it almost 2 centuries old! The stillness of the air added an eerie feeling to this abandoned religious site.

Beautiful speleoterms at the entrance of the cave. Note the large stalagmite in the centre resembles a sea lion.

The abandoned Chinese Temple.

Loose guano (bat droppings) on the ground across the cave indicates it has been relatively untouched by man for a long period of time.

However, it is not this temple that is the most interesting here. We'll leave this to the athropologist to explore instead. Following our guide up another flight of steps to a smaller chamber off the main cave, we gazed across the rock wall, anxious to catch a glimpse of the well-known attraction. Up here, the limestone abruptly gave way to irregularly shaped brownish ancient mud deposits stretching up to the chamber's roof with occasional exposure of the underlying limestone at eroded and fall-off chunks areas. We used torches to assist our search. An area close to the roof sparkles and shines under the beams of light emitting from our torches. This is the main highlight and the namesake of the cave - an almost complete set of mammalian fossil embedded in the drab rock. It was first discovered by the Malaysian Nature Society when they were on an expedition to survey karsts of Kinta Valley. Since then, there were many views to its possible species including mountain goat, leopard and wild cat. However, no positive identification can be obtained yet as the skull and many other parts are half embedded and eroded. Besides, there's little interests in researching the bones to date.

The mudstone encrusted chamber where the fossil was found.

A general view of the mammalian fossil. Note: the eroded skull below the piled up front limb bones at the bottom-left section of the picture.

After spending some time speculating about its species, I decided to scour the ground instead for other interesting critters. Sure enough, I discovered a "stone-anvil" commonly used by predatory birds to crack snails' shells for their meat. There are also some bat bones nearby, which probably means this cave is home to bat colonies although none have been spotted during our presence there. Another pleasant discovery, a first for me, is a rock containing brochiopod or bivalve like fossils stacked under a pile of limestone.

A predatory bird's victim Cyclophorus malayanus (Benson 1852), smashed into pieces on a rock.

Bone fragments of a bat lying on the dry cave floor.

A fossil embedded rock, probably a group of bivalves or brachiopods.

The sun soared over the hill and it was time for us to bid farewell to this fascinating cave. As we decended, the midday sun shines upon the taller karsts at the distance, exposing vividly every hue of the blasted limestone cliff and reminding us how fragile these beautiful hills are. Hopefully, this rare natural heritage that could be of huge significance in national and regional paleontology will be protected and preserved indefinitely.

Some articles and reports of similar interests:
1.Star Metro (Wednesday October 7 2009)- Good Lord! It's a leopard!

2.Heritage news (November-December 2008)- Rock of Ages: Treasures of Malaysia

3. Liz's site: Gua Tambun & Naga Mas

4. Adi Taha Harnessing Science and technology for preservation and conservation of cultural heritage of Malaysia, Department of Museum and Antiquities.

5. R.F. Muhammad, D. Yoshida, A. Tani & P.L. Smart (2002) Implications of Electron Spin Resonance and Uranium-series Dating Techniques on Speleothems in the Kinta and Lenggong Valleys, West Malaysia Advances in ESR Applications, vol.18 pp.19-26, (2002)

6. Liz Price 2008 A Speleotourism In Peninsular Malaysia Pesquisas em Turismo e Paisagens Cársticas, 1(2), 2008

7. Caves of Malaysia: The Sun (20 October 2008)- No protection for Gua Naga Mas' Fossil

Freshwater whelks, anyone?

Sea whelks from the family Buccinidae has been a common food for many cultures especially those from polar and temperate regions. But have you ever heard of whelks from rivers and lakes? For the aquarium enthusiasts, this may have struck a chord in them. Freshwater whelks (a.k.a. assassin snails) are well-known for their ability to "massacre" almost the entire population of aquarium snails in just a matter of hours! Yes, they are carnivorous and vicarious snail-eaters - the ultimate weapon-of mass-destruction for those who wanted to make their snail-infested aquariums a thing of the past.

Clea helena (Meder in Philippi 1847) from Sungai Jernih, Perlis, northern Peninsula Malaysia. Note its difference from Thai varieties offered in the aquarium trade.

On the scientific front though, little is known about this enigmatic group of snails. However, it is generally accepted that there are two genus of this family that somehow abandoned the sea in favour of creeks and ponds. The African species is categorised into the (sub)genus Afrocanidia while Asia's is grouped into the Clea genus. Now, this may shed some light to its origins. Perhaps, they first appeared from a common ancestor when Africa and South Asia was in one piece (called Pangea) 225 million years ago? or did they adapted to freshwater separately (convergent evolution) since it is more likely to be a recent adaptation?

Steung Saen, Kampong Thom, Cambodia. This is the preferred habitat for Clea species as it has a wide, muddy river bottom. Such habitats are widespread across delta plains of Southeast Asian countries.

Information on the African species is particularly void while Asia's ones received more attention (from the aquarium trade, not researchers!). Clea genus is widespread across Southeast Asia and have not been recorded elsewhere. It's abundance is notable especially in alluvial plains and around large water bodies like the Irrawaddy delta (Myanmar), Mekong River (Indochina countries) , Chao Phraya River (Thailand) and other major waterways and lakes of Malaysia, Brunei and Indonesia (Sumatra, Java, Kalimantan). The question is - how did they managed to reach other rivers and lakes divided by tall mountain ranges and vast seas?

Sungai Jernih, Perlis, northern Peninsular Malaysia. Another typical habitat for many Clea species as they have abundant prey to feed on and nutrient-rich waters flowing from nearby caves.

The possible answer can be found when we turn the clock back to around 20 000 years ago. The waters of South China Sea, Gulf of Siam, Straits of Malacca and Java Sea recede and is replaced by alternating grasslands and swamps. Now, one would notice that major rivers were being drained out of this large peninsula, dubbed Sundaland, by "mega rivers" (much like the present day Amazonian Basin). So, it's possible that the Clea genus or its ancestor have had its early millenias conquering much of Sundaland's freshwater systems before rising sea levels cut off many populations and from there each evolved into seperate species or subspecies.

Alright, the next big question is probably: How does it feed? I have heard many who discovered them congregating around rotting carcasses of frogs, dead swiflets and bats near caves. Personally, I have encountered a group of Clea helena feeding on picnic leftovers of fried fish at water's edge in Sungai Jernih, Perlis, Malaysia. So, these buccinids are no different from their marine cousins- scavengers and predators at the same time. I've brought some back home for further observations of their feeding behaviour. Here's a photo-essay of it:

Clea helena is a very resilient snail. It can lay dormant for more than a month without food. In this stage, it usually buries or half-buries itself in the loose, sandy or muddy substrate.

When food (meat or snail) is detected, it prolongs it's proboscis (siphon) and crawls out to search for its quarry. Occasionally, it will also react similarly when there is movement in the water (especially if it lives in still waters most of the time.)

It will then wander around to locate the prey. However, it takes a straight path towards the prey if there are no others in the vicinity.

Usually, Clea snails can be found in abundance when present in a water body. Thus, when a prey is detected, a large number of snails will search and assemble around it.

The first to reach the prey will grab it with its foot and inserts a thin, fleshy tube (siphon) into the snail and suck the animal within the shell. (Proably excreting digestive enzymes and dissolve the prey alive before consuming it.)

Meanwhile, other Clea snails will try to loosen the grip of the feeding predator on its prey by using their foot to "pull" the prey out, much like a tug-of-war game.

It takes about half an hour for Clea helena to finish its meal but that may be because of the miniature size of the prey. For larger size meals like frog carcasses, it might take a day or more to finish the entire body. Most of the time, they will abandon their meal when they are full and return back when they're ready for the next meal.

After some time devouring its prey, other snails will lose interest and gradually retreats back to their hideouts, leaving the lucky snail and its meal alone. At last, when the meal is finished, the predator will crawl back to its own resting spot, leaving empty shells of the prey behind.

Overally, Clea species feed like their marine cousins. Although Clea helena is the most well-known in the genus, there are plenty of other species. Here's a list from Ocean Biographic Information System (OBIS)-Indo-Pacific mollusc database :
Clea bangueyensis (E.A. Smith 1895)
Clea bocki (Brot)
Clea bocourti (Brot 1876)
Clea helena (Meder in Philippi 1847) synonym C. theminckiana (Petit 1853)
Clea hidalgoi (Crosse 1886)
Clea jullieni (Deshayes) synonym C. bizonata (Deshayes)
Clea nigricans (A.Adams 1855) (Click here for a photo showing a group of them feeding in-situ)
while Clea gemma (Conolly 1929) is the type for the Afrocanidia (sub)genus from Africa.

Not surprisingly, Buccinids aren't the only one which has migrated to freshwater environments in Southeast Asia. There are also genus Nassodonta (East Asia), Pygmaenassa (India) and Arcularia (Lake Chilka, Burma) from Nassariidae, Rivomarginella (Southeast Asia) of Marginellidae, various genus from Neritidae and Morrisoneitta (Thailand) of Pyramidellidae. So, who knows what more lurks in the muddy depths of these tropical rivers and lakes?

(Click here for a link about Clea helena's reproductive cycle.)

Reference and Further Reading:
1. Trew, A., 1987. The Melvill-Tomlin Collection. Parts.50,51,52,53,54. Buccinacea (Pyrenidae, Buccinidae, Galeodidae, Nassariidae and Fasciolariidae).

2. Edlic Sathiamurthy and Harold K. Voris, 2006 Maps of Holocene Sea Level Transgression and Submerged Lakes on the Sunda Shelf. The Natural History Journal of Chulalongkorn University, Supplement 2:1-44, August 2006. (click here)

3. Ellen E. Strong, Oliver Gargominy, Winston F. Ponde, Phillippe Bouchet,2008 Global diversity of gastropods (Gastropoda;Mollusca) in freshwater. Hydrobiologia (2008) 595: 149–166 (click here)

4. Seiji Hayashi,2005. The molecular phylogeny of the Buccinidae (Caenogastropoda: Neogastropoda) as inferred from the complete mitochondrial 16S rRNA gene sequences of
selected representatives. Molluscan Research 25(2): 85–98 (click here)