12 June 2013

Sentosa battered by blue drums?

How are the seagrasses doing on Sentosa? Particularly after the installation of the massive blue drums as part of a 'security barrier'.
I had a quick look as part of TeamSeagrass monitoring of this shore.


In some parts of the shore, there was quite a bit of seagrasses, even near large pieces of rubbish like tyres.
Oh dear, I came across many patches of Tape seagrass (Enhalus acoroides) that have their leaf blades 'cropped' so that they stick out of the water.
Not all of Tape seagrass was cropped though. There were also many clumps that were still nice and long.
I came across some small patches of Spoon seagrasses (Halophila ovalis) that were severely bleached. Most of the green stuff (chlorophyll) was lost, leaving only a green outline and green mid-rib on a transparent leaf.
Here's my attempt at a close up in very windy water.
It was heartening to see several clumps of Tape seagrasses producing many young female flowers.
It was a very windy day, in high water, with lots of waves from passing high-speed boats. Monitoring alone, I had to step on the transect so it wouldn't move. Needless to say, the transect photo shots were very poor.
Here's a look at some of the seagrasses I saw today.
Today I had my first personal close up look at the the blue drums that rests on the shore at low tide. These are part of a floating 'security barrier' installed in 2012. Pei Yan blogged about these barriers in April 2012.
The blue drums rattle loudly as they bash up and down in the high waves generated by boats and ships that pass by at high speed.
This video clip gives a better idea of the rattling (the sound on the clip is not just the wind).

The drums bash coral rubble where all kinds of animals may shelter and hide.
One of the rocks near the blue drums seems recently smashed (yellow arrow). Due to the drums bashing on it?
Rocks are naturally coated in a mini-meadow of algae which supports all kinds of animals. The chains and drums scrape this away.
Both Spoon seagrass and Tape seagrasses are found near the blue drums.
Some animals seen near the drums include Frilly sea anemones, small corals, some clumps of soft corals and on the rocky shores, all kinds of little snails.
On the sandy area near the blue drum, I noticed the track of a bird (yellow arrow) and a monitor lizard (orange arrow).
And what have we here? It's an octopus. In fact, Sentosa is one of the shores where I can be almost certain to see an octopus even during the day!
OK, I cheated. I saw it swimming about before it settled on the bottom, perfectly camouflaged.
This natural shore also has some special plants that are now rarely found in Singapore. Like these two Nyireh trees (Xylocarpus rumphii) which are Critically Endangered.
The natural cliffs of this Sentosa shore is home to probably the last largest group of Sea Teak (Podocarpus polystachyus) found naturally in Singapore. Other interesting plants include Raffles' pitcher plants (Nepenthes rafflesiana) and Delek air (Memecylon edule). All these plants are on the Singapore Red List of threatened plants.
I had a quick look at the high shore. There are curious crab holes, interesting shells and corals washed up as well as some litter (we really can't run away from litter anywhere on the planet anymore I think).
This last stretch of natural shore on Sentosa lies near the massive Pasir Panjang Container Terminal reclamation project, which can be seen on the horizon.
I didn't get a chance to see much of this shore or the northern side of it behind Underwater World Singapore. There are so many of our lovely natural shores at risk and not enough time or tide to monitor all of them.

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