Wednesday, January 14, 2009

Soft sediment creatures of Pasir Ris

Pasir Ris Park is well known for being a manicured recreation spot for people to rest, relax or even exercise. Usually during high tides or not-so-low tides, shore-goers usually just see the whiter sandy part of the shore. But if you take effort to take a look during a good low spring tide, you will realize that there are portions that look muddy and uninviting.

In fact Pasir Ris shore is a good example of a soft sediment shore that houses many different types of marine creatures, some of which I am going to share with you below.


This alien looking creature is actually a hairy sea hare (Bursatella leachii). They are are usually well camouflaged and blend in perfectly with among seaweeds and seagrasses. However, please do not try to disturb this sea hare because it produces a purple ink when stressed up.


Later on, I saw this slug-looking creature which we have no idea what it was. The blue spots on its body look like the above sea hare and probably it is a dead one that has lost its hairy projections.


On a narrow portion of the shore, we found several empty shells that probably belong to Phalium glaucum of the Family Cassidae (Helmet shell snails). More about these snails on Ria's wildshore blog.


If you think that floating leaves on the seashore are boring stuffs, you are wrong. The underside of these seeming floating leaves are actually moved by leaf porter crabs.


Like Chek Jawa, there are many tubeworms teeming the sandy part of the shore.


Other than the tubeworms, there were large mats of Asian date mussels (Musculista senhousia). The interesting thing is that they were only sighted right in front of the freshwater discharge area. This suggests that either they favour low salinity, or that competition for niche is less on such fresher parts of the shore.


On soft sediments, sometimes you might encounter worms surfacing.


This is another worm that is orange in colour. Though it appears pretty, identification can be quite a headache!


This striped bead anemone is usually encountered on our northern shores.


The brown body column of this striped bead anemone has pinkish bumps.


Peering harder into what is seemingly lifeless sediments, I saw this tiny weeny anemone that I don't know what it is exactly.


Soft sediments support several types of anemones and this is a tiger anemone.


Though not as common as in Changi, there were still a couple of Haddon's carpet anemone (Stichodactyla haddoni).


Of course, peacock anemones are colourful additions to the shore and they come in all sorts of colours.


Sometimes if you look closer at the Sea lettuce (Ulva sp.), you might also spot creatures that reside in or underneath it like this tiny juvenile peacock anemone.


Ria found this tiny flatworm with her amazing eyesight. I don't think I would have seen it given that the colour is similar to the sand.


What is interesting of this flatworm is the presence of two tentacles! Read more about this weird flatworm at Ria's wildshores blog.


I was surprised when I saw this See-through sea cucumber (Paracaudina australis) sticking out of the sea lettuce meadow. At first I thought it was a peanut worm.


However, this sea cucumber has short feeding tentacles but they are still cute isn't it?


As dusk fell, the stars started to twinkle the beach. :-) Like this brittlestar.


And plenty of my favourite sand star (Astropecten sp.)...

and this juvenile cake sea star (Anthenea aspera).

Sometimes, we need to know that these marine creatures are present before we can appreciate them. So don't dismiss any shores, or even reclaimed shores, as lifeless. Soft sediments are great substrates for creatures to crawl around.

2 comments:

HELEN said...

hi, great sightings! where exactly were you at? would like more information, mind if i get your email contact?

koksheng said...

Hi Helen, if you like to explore Pasir Ris, you might find it convenient to explore the part right in front of the Downtown East area at a good low spring tide. However, the shore is VERY soft so be very careful. Let me know how the trip went, I'm excited to hear your adventure.

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