Wednesday, January 28, 2009

Sentosa on 27 Jan 2009

It's been a while since I last visit the shores of Sentosa, and so on Lunar New Year Day 2, LK, ST and I decided to visit this little island. Tide wasn't really very low, and so I didn't really expect to see many things. But guess I was wrong :)

Sentosa cliff
One of the things that kept drawing me back to Sentosa are the beautiful coastal landforms - spectacular cliffs, pretty arches, mysterious caves... You can find all of these at the rocky shore.

Rocky shore
Signs of erosion at the shore, where the softer rocks were eroded and swept away by the waves, and the remaining harder rocks forming parallel ridges.

The last time I was here, there was a landslide on this slope. Some kind of reinforcement concrete has been built since then to ensure the slope will not slide down again.

Sand-sifting sea star (Archaster typicus)
On the sandy shore, I found a little sand-sifting sea star (Archaster typicus). This is a rather common sea star, and we have seen it on many of our southern islands, sometimes in the hundreds.

Carpet anemones (Stichodactyla haddoni)
There were several huge carpet anemones (Stichodactyla haddoni). These are animals with lots of sticky tentacles to capture their prey, such as little fishes or crabs.

Sponges were a common sight here too. These are also animals, and they feed by filtering for tiny food particles in the water sucked in through little pores on their body. The sponge above is Pseudoceratina purpurea.

Some sponges may look like seaweeds or even hard corals, like the Lamellodysidea herbacea sponge above. You can tell them apart from the pores and that they usually do not have a hard skeleton.

Montipora branching coral
And here are the real corals - the branching Montipora hard corals, growing among colonies of green ascidians.

Turbinaria coral
Hard corals come in various growth form, and some may look like somewhat plate-like or flower-like, like the Turbinaria coral above.

Porites coral
Others, like the Porites coral, may look like a rock.

Coral poylps
But if you look closer, you will realised that they all have little holes on them, and that's where all the coral animals, called polyps, live. The coral is basically like a HDB flat with lots of little occupants! Sometimes, corals may also fluoresce. This is due to their colour pigment, which supposedly helps prevent them from getting dun-burned.

Boomerang mushroom coral (Herpolitha limax)
While most corals are attached to the substrate, there are some, like the boomerang mushroom coral (Herpolitha limax), which are free-living.

Lobophyton soft coral
Not all corals are hard - we have soft corals too! Sentosa is also a good place to find huge colonies of soft corals. The above is a Lobophyton sp.

Tape seagrass (Enhalus acoroides)
While the corals are often mistaken for plants, here are the real plants - tape seagrass (Enhalus acoroides). Note that I'm refering to the long ribbon-like ones, not the hairy ones. Those are Bryopsis green algae.

Halymenia red algae
It appears that there is a Bryopsis algal bloom, and we can see them every where. But among the green patches, there were a few red patches of red Halymenia algae too. Kind of an auspicious colour for the Lunar New Year :P

Giant reef worm (Eunice aphroditois)
This giant reef worm (Eunice aphroditois) gave me a surprise when it suddenly appeared next to my feet. And of course, I immediately turned my camera towards it. Unfortunately, its head was hidden under the algae though.

Nudibranch (Dendrodoris denisoni)
Other interesting animals I spotted and remembered to take a photo include this little dendrodoris nudibranch (Dendrodoris denisoni). It was sliding over the sandy substrate when I spotted it.

Funeral nudibranch (Jorunna funebris)
There were quite a few funeral nudibranchs (Jorunna funebris) among the seaweed too.

Giant top shell (Trochus niloticus)
At the rocky area, I found this giant top shell (Trochus niloticus). This huge snail feeds on algae.

All too soon, the tide was rising and we had to leave the intertidal area. On the whole, it was quite a relief to find the intertidal area still doing fairly well despite the development work been carried out in the surrounding areas. Will probably visit this shore again during a lower tide.

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