11 March 2011

"White mud" at Pasir Ris, and check on rare mangroves

The burrows of mudskippers at Pasir Ris were ringed with 'white mud' today. How strange!
I also had a quick look at some of the rare mangroves at Pasir Ris Park, and only now noticed ANOTHER Lenggadai tree there.

Giant mudskippers (Periophthalmodon schlosseri) dilligently dig impressive burrows in the mud. They do this by tirelessly spitting out mouthfuls of mud from deep in the mud. Usually, the mud that is spat out from below is grey. Today, I only saw these two burrows with the typical grey mud around the opening.
Most of the burrows I saw were ringed with 'white mud'. And I saw a lot of such burrows, all along the boardwalk from the beginning towards the end near Sungei Tampines.
The mud is probably spat out very recently, as otherwise the incoming tide would have disturbed the 'white mud'. Some of the mudskippers seem to have been very busy and hard at work.
While others seem to have only spat a few balls of mud out of the burrow.
I'm not sure what the 'white mud' means. [Update: Dr John Yong kindly shared this on facebook about the 'white mud': The white mud is probably the commonly available kaolin type of mud previously used to fill up this 5-ha mangrove forest. Some of the other darker white patches may be due to the accummulation of elemental sulphur that did not get wash awa by each tidal inundation. The sulphur is a result of the anaerobic bacterial activity (from Hydrogen sulphide).This mangrove forest still lacks an appropriate tidal innundation of sea water. You need the sea water to wash away, periodically, the white elemental sulphur accumulated at the middle and back mangrove areas. Thank you Dr Yong!]

I was trying to take better photos of these large and common mudskippers. Especially with their dorsal fins raised. I had no luck today even though there were very many Giant mudskippers at Pasir Ris.
While at Pasir Ris, I'm always delighted to check out some of the rare mangroves that have been planted in the Park. The stand of beautiful Berembang (Sonneratia caseolaris) are very tall now and blooming and fruiting! A great opportunity to photograph the flowers and fruits in various stages of development. I probably need to visit one night to catch the night-blooming flowers at their full glory.
The Gedabu (Sonneratia ovata) was also fruiting, with some buds ready to bloom.
While the short Tumu berau (Bruguiera sexangula) was blooming and 'fruiting' too!
Besides these planted mangroves, there are also some natural rare mangroves at the Park. The Lenggadai (Bruguiera parviflora) was blooming and also forming propagules!
Lenggadai had long narrow flowers which develop into propagules with the calyx clasping the long green part. The more common Bakau putih (Bruguiera cylindrica) has small short flowers which develop into propagules with the calyx bending away from the long green part.
And what a surprise! Today I noticed ANOTHER tall Lenggadai nearby and it too was flowering! To think I've been visiting this spot for so long and never noticed the other tree, which is quite tall and healthy looking!
Sadly, I noticed that large swathes of the mangroves in the Park are still badly affected by sooty mould which turn the leaves black.
And like many of our mangroves, erosion is affecting some of the trees near the larger channels. The loss of the mud reveals the usually buried roots of these trees.
On a happier note, I was glad to see that lots of herons are still nesting and hanging about at Pasir Ris mangroves!
Another thing I noticed today were many different kinds of orchids that had been fixed onto the big trees in the park. Some of them were blooming! How nice!
There were also many clumps of massive orchids planted in the park. Possibly Tiger orchids?
So do drop by and visit this fascinating Park. Besides the mangroves, there's also a nice kitchen garden, as well as of course the sea shores!

There's many guided walks and other interesting activities at the Park. Check out the NParks website and wildsingapore happenings (enter "Pasir Ris" into the search bar).

Some exciting upcoming events at Pasir Ris include:

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