20 October 2008

Somewhat low on Changi

Often dismissed as reclaimed land, Changi has among our more delightful mainland shores.Although the tide didn't go as low as expected, we still encountered colourful creatures such as psychedelic peacock anemones (Order Ceriantharia) .

When the tide isn't low, the water is murky as waves splash onto the shore.
Nevertheless, a careful look will turn up tiny little flatfishes, like this spotted one which may be a Tongue-sole (Family Cynoglossidae). And another tiny one lurking in the sand, which may be a young Commerson's sole (Synaptura commersoniana).A Kite butterflyfish (Parachaetodon ocellatus) glides by in the murky water.

As the tide finally falls, the sandy areas are the first to have clearer water.This is not a sea anemone! It's the feeding tentacles of the buried Ball sea cucumber (Phyllophorus sp.).How nice to see lots of sea pens (Order Pennatulacea) on Changi. This sea pen looks more like a pencil so we've dubbed it the 'sea pencil'.

A sea pen is a colony of separate and different kinds of animals that live together. Here is another kind of sea pen, probably a member of Family Veretillidae.One of the colony members is the polyp that looks like a tube topped with tentacles. This gathers food for the colony.Like other soft corals, sea pens have eight tentacles which are branched (the hair-like projections from the tentacles).Sand stars (Astropecten sp.) are of course often found on sandy areas. There were also lots of sand dollars (Arachnoides placenta) and Chay Hoon spotted a patch of Button shell snails (Umbonium vestiarum).

Changi also has seagrass meadows, mainly full of Spoon seagrass (Halophila ovalis) and Fern seagrass (Halophila spinulosa). We noticed the patches of Needle seagrass (Halodule sp.) have grown more extensive.
Among the seagrasses are all kinds of other animals such as this tiny Biscuit sea star (Goniodiscaster scaber).Tiny sea anemones also settle on seagrasses. This might be Stichodactyla tapetum and not a tiny version of Haddon's carpet anemone (Stichodactyla haddoni).Like prickly tennis-balls, the large White sea urchin (Salmacis sp.) is still seen all over the seagrass meadows, although the skeletons of many were also seen washed ashore.

There were also large clumps of green Mexican seaweed (Caulerpa mexicana).This green mini-forest provides shelter for all kinds of animals.These include tiny snails and tiny beachfleas.
Tiny hermit crabs in tiny snail shells.Tiny baby swimming crabs that might grow up to become our seafood dinner.
Tiny shrimps that blend in with the seaweeds. Chay Hoon saw lots of wooly Elysia slugs, but I couldn't find any :-(More colourful thorny sea cucumbers (Colochirus quadrangularis) cling to seaweeds and seagrasses.These tiny animals are in turn eaten by large ones. Indeed, several busy mantis shrimps (possibly Harpiosquilla sp.) were hunting through this mini-forest. Thus the seaweeds and seagrasses support a food chain that includes the seafood that we eat.

At the same time, Kok Sheng, Chee Kong and friends were working on another part of Changi and saw more stuff! Our Changi shores are truly amazing.

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