23 August 2013

Seagrassy Pasir Ris Park

There's lots of great, fresh green Spoons seagrass at Pasir Ris! Some interesting marine life too.
Sadly, lots of questions and possible threats to Pasir Ris marine life.


Common cerianthids (Order Ceriantharia) were the most abundant animal on the shore today. And most of them had lots of Black phoronid worms (Phylum Phoronida) living with them.
Here's a closer look at the Phoronid worms. They have a double pair of feathery spiralling tentacles on a long unsegmented tubular body. It is believed that the body of the phoronid worm penetrates the tissues of the cerianthid but the phoronid worm is not parasitic and does not absorb nutrients from the cerianthid directly. Sounds rather creepy to me.
It was nice to see several Tiger sea anemones here. Looking through my records, it seems it's my first time seeing it at Pasir Ris. These sea anemones are more common at Changi.
I saw two Spiky sea pens (Ptreoides sp.), I couldn't find porcelain crabs in either one.
I saw several small Haddon's carpet anemone (Stichodactyla haddoni) and a few small Mini carpet anemones (Stichodactyla tapetum). There were many Sand striped sea anemones.
How nice to see a goby (Family Gobiidae) and a snapping shrimp (Family Alpheidae). I don't think though, that they are the kind that live together in the shrimp's burrow.
There were some small Striped hermit crab (Clibanarius infraspinatus), many small Flower crabs (Portunus pelagicus) and I saw one Leaf porter crab (Family Dorippidae) carrying a shell. There were also many small Stone crabs (Myomenippe hardwicki) hidden in holes and under rocks.
I saw one Calf moon snail and several clams. There were also many Spiral melongena snails (Pugilina cochlidium) as well as Drills (Family Muricidae) of various kinds.
There were many Plain sand stars (Astropecten sp.). I saw one Cake sea star (Anthenea aspera) and only one medium sized Biscuit sea star (Goniodiscaster scaber). There were some Ball sea cucumbers (Phyllophorus sp.) among the seagrasses, but I didn't see any other kind of sea cucumber. Surprisingly, I didn't see a single sea urchin although there are lots seen recently at nearby shores.
There was a large pile of snail shells and when I turned some over, most were Drills but a few were occupied by hermit crabs. They all seemed to be gathered to eat something.
There are small rocks  here and there at the low water mark. They were mostly bare with hardly any growths, unlike nearby shores like Changi. I only saw one small patch of Rainbow sponge (Suberites sp.) and a small cluster of Purple branching sponge (Callyspongia sp.) as well as a few Ball-tip corallimorphs.
Some of the rocks had small sparse patches of Zebra coral (Oulastrea crispata). Only a few patches were larger, like this one.
I saw a small cluster of what might be Cave corals (Tubastrea sp.).
Under a rock, there was a small toadfish (Family Batrachoididae)! The shore was rather quiet and I didn't see any of the animals that were abundant during my last trip here in Jul 2012.
What a delight to come across small patches of Hairy spoon seagrass (Halophila decipiens) (yellow arrow), usually closer to the low water mark than Spoon seagrasses (Halophila ovalis) (blue arrow).
Here's a look at a patch of the Hairy spoon seagrass. I came across one patch that was fruiting, with what seems to be one flower!
Here's a closer look at the fruit and some of the super tiny seeds inside the fruit. The seeds sink rapidly when the fruit is opened.
On the high shore outside the Pasir Ris Park boundary, there were some interesting mangrove trees and coastal plants. These can have pretty flowers if we take a closer look! Sadly, there's a great deal of litter among these plants.
There were a few people fishing on the shore.
There is still a great deal of erosion at Pasir Ris (yellow arrow), even after the massive works done to correct this problem in 2011. I noticed a lot more gravel laid around the hard walls (blue arrow). But there's lots of fresh thick Spoon seagrasses growing on most of the shoreline near the low water mark (orange arrow).
I noticed stacks of sandbags laid on some parts of the shore.
The underlying clay on the high shore is starting to show up from the layer of sand that was probably laid on top of it.
The layer of sand on the beach is very thin. This is what I saw in 2009 when massive works were being done at Pasir Ris in 2010.
Taken in Dec 2009
There are other issues impacting Pasir Ris and I've done separate posts about them. From strange goings on with the line of floating blue drums, a security barrier that runs parallel along the beach. Like this floating structure on the inside of the security barrier. What is going on? More photos and other questions in this post.
Outside the Pasir Ris Park boundary, there are a series of long pipes leading out of the forested area. Where exactly do these pipes come from? Are these pipes approved? What is being discharged through these pipes? More photos in this post.
Pasir Ris has always been a trashy shore since I started surveying it. What is going on? Where does the trash come from? Lots more sad photos in this post.
I only covered a small part of the very long Pasir Ris shore. I shall try to revisit the rest of the shore eventually. Tomorrow is the last morning super low tide of the year. There will be few good low tides until November. There are not enough low tides to look after all our shores at risk.

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