24 December 2011

Wet at Cyrene with flooding at sea

It's fun and enjoyable to join Siti in her seagrass field trips! We get to enjoy complimentary drinks on a lovely boat, leaving from a very posh marina. In great company too!
The plan was to show what a great trip we have when we are out helping Siti. But ...


It started to rain. Very heavily. We could barely see the port just a short distance away from where the boat was anchored off Cyrene.
As we were waiting for the rain to let up, we watched in horror as a boat roared at full speed TOWARD the reef! We were all getting ready to rescue passengers when at the last moment, the boat turned sharply away and all was well again.
Finally, the rain eased up after the last of us put on his special, custom-made poncho. We know that the weather usually eases up when everyone puts on their ponchos. So we headed out for the reef.
The tide was a tad high as we sloshed towards Siti's seagrass experiment in the middle of the reef. It was still raining. We could hardly see the huge vessels passing by the reef.
Aha, finally, a stretch of sand bar and Siti's experimental frames are in the distance.
As soon as we arrived we got started on cleaning the frames of the growths of barnacles that rapidly grow on them. We have kept on our life vests as they keep us nice and warm!
While we scrape, Siti and Nor Aishah take seagrass readings in the frame.
Then it was time to reattach the shading screens on the frames. Cable ties do the job perfectly! Many of us have recently become aware of the importance of cable ties. As elsewhere, cable ties are a critical part of Siti's project!
Wet and soggy, covered with barnacle bits, we head back home. Along the way we meet some of the amazing marine life on Cyrene. Lots of huge Knobbly sea stars (Protoreaster nodosus) as usual.
Also many Cake sand dollars (Arachnoides placenta), Common sea stars (Archaster typicus) many in mating position, lots of White sea urchins (Salmacis sp), some baby Knobbly sea stars and I saw one Egg white moon snail (Polinices albumen) burrowing in the sand.
So you see, despite the horrible weather, we DO have a great time out with Siti! It's even more fun when it's sunny!
Just as we approached the marina, we noticed a huge swathe of brown water, in stark contrast to the blue water elsewhere.
The brown water covered a large area near the shore, even to the natural shores at Sentosa.
Did the brown stuff come from the massive reclamation for the new Pasir Panjang Container Terminal?
The water got browner as we arrived at the marina which is tucked away from the sea. How did the brown water get into the marina? Or...
More likely the brown water came mainly from the mainland during the downpour. That's why it's more concentrated in the marina? We asked Alex, who is wise about these things, and he said yes, when it rains, this happens. Oh dear!
Sedimentation is really bad for marine life as it clogs up delicate feeding and breathing parts, and blocks out the sunlight which many animals depend on, especially animals that harbour symbiotic algae (zooxanthellae) which make food from sunlight and share the food with their animal hosts. These include corals.

I didn't realise that a downpour can result in such a flood of sedimentation in our coastal waters!

2 comments:

  1. From post: "More likely the brown water came mainly from the mainland during the downpour."

    The photos of tons of silt-laden water draining from the mainland into the sea are indeed a stark reminder of how a lack in Earth Control Measures (ECM) also negatively impacts the nearshore & its inhabitants.

    Since this involves drainage outlets, maybe you could consider sharing your first-hand observations & photos with PUB.

    Meanwhile, since such silt pollution is of multiple origins & recurring frequency, perhaps PUB could proactively explore alternative technologies to filter out such silt & other sediments, before the polluted water flows out to sea or into major waterways.

    I wonder if the new GLASSwater membrane (S$50-100/ sqm) might help ? This porous ceramic filter-membrane has a high flux, so water flows through it very rapidly. Can such membranes be installed across the drainage outlets of known polluting sources, at outlets draining into the sea, or even at major inlets to canals ?

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  2. Thanks for sharing these thoughts Pat.

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