23 June 2009

East Coast Park Rocks!

A rock or a hard place is exactly what many kinds of marine life need! So much so, that such hard surfaces can become encrusted with a bewildering variety of life.
And this was the glorious sight that awaited us at East Coast Park!

Earlier on, Kok Sheng had done a recce to find some promising sites to explore. Thanks to his hard work, explored a few spots on this our longest coastal park.

The most profusely encrusted areas of a hard surface are the lower portions that are submerged most of the time. During today's super low pre-dawn tide, we had a brief glimpse of these.
Jammed next to one another are colourful sponges and hydroids of all kinds. Although resembling colourful plants, these are actually animals. They have plant-like forms because they filter feed from the water current and thus maximise their feeding area. Thus their forms resemble plants which also maximise their area for 'feeding' off sunlight.

There was a lot of these animals which I think is a sea fan that is rather knobbly.
In addition to the large pale pink sea fan that resembles a tree (first photo above), James also saw a bright red one!

Looking floppy and sad when exposed out of water, are these Pink flowery soft corals (Family Nephtheidea). When submerged they fluff up, expand and resemble bushes. Each is a colony of many tiny polyps.
There are even these tiny hard corals stuck among the riot of life. They may be Cave corals (Tubastrea sp.) which grow in dark places.
Nestled among these branching animals are animals that look like blobs and slimy layers. They are ascidians. The purply slimy layer is probably a colonial ascidian made of many small animals. While the white blob with orange stripes is a solitary ascidian which I call a Thumbs up sea squirt (Polycarpa sp.). With one long and one short siphon, it does resemble a fist in a thumbs up pose.
These animals are often preyed upon by other animals such as nudibranchs. And indeed, we were quite excited to see the Bornella nudibranch (Bornella sp.)!
This slug has a long, narrow body. There are two rows of finger-like appendages along the body. Delicate transparent feathery gills are on these appendages. There are star-shaped oral tentacles near its mouth. Wow, so far I've only seen this nudibranch near reefs.

As we look upwards where the hard surface is more often exposed out of water, things get a little less crowed. But still, the surface is coated with life, such as thin but colourful encrusting animals and these elegant branching sponges.
Even further up where the hard surface is often exposed out of water, the barnacles settle. As well as small oysters and clams. The shells of dead and living barnacles, crowded next to one another, create all kinds of nooks and crannies for MORE animals. Today I saw a tiny polychaete worm sneak out from its hiding place, while a Purple climber crab (Metopograpsus sp.) wedged itself into a crevice.
Barnacles are favourite food for some Drills (Family Muricidae) which can actually drill a hole through the barnacles' shells. These yellow tubes are Drill egg capsules, laid among the barnacles! And the tiny little snails are Periwinkles (Family Littorinidae). I'm not sure what they are doing on the egg capsules. There are slugs here too! The little Onch slug (Family Onchididae), however, is not carnivorous. It just grazes on the film of algae that grows on hard surfaces in the sea.

Drills are infact quite plentiful on hard surfaces. I peeked into a drainage pipe and found large areas covered in Drill egg capsules! The capsules are yellow and turn purple when the young hatch.
Even in the barnacle zone, there are thin layers of what look like colonial ascidians. Lots of tiny crabs are found here too. And Lined bead anemones (Diadumene lineata) that look like tiny blown glass ornaments.
As it was a really low tide, we could peek at what might grow at the base of the man-made seawalls.
And surviving the pounding waves, are thickets of delicate skinny sea fans!
These too are animals, in fact each branching colony is made of many tiny polyps. They come in bright psychedelic colours!
And here's another bunch of them.
The tough Zebra coral (Oulastrea crispata) also grows here, forming a low encrusting colony.
Amongst the riot of colourful marinelife are the equally colourful and lively Sally-lightfoot crabs (Grapsus albolineatus).
While all this is quite exciting, there's MORE shores to see on the East Coast. We also head out to check out a sandy shore, and on the way back, dropped by to have a look at the East Coast Lagoon.

All this even before sunrise!
It was tiring but quite exciting to know that East Coast Park does have interesting marine life!

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