Sunday, March 23, 2008

Discovery @ Semakau on 21 March 2008

Fifty Second Discovery Posting:

It was Good Friday (21 March 2008) and a batch of us were out on Semakau with Dr Dan and his group of students. Although this was a trip especially for Dr Dan's students who were from Duke University to explore our shores, i didn't really play a good host to them as i had other ideas on mind for going to Semakau =P.

Well, I was hoping to locate juvenile knobbly sea stars (Protoreaster nodosus), wanted to do it because CK couldn't find any of them during the last exploration trip and my mini study on them was still on.

As i was walking away and probably much ahead of others, i didn't manage to spot as much things as them, probably because i only have one pair of eyes. =P

But after about 20 minutes and not much luck in spotting anything, I saw my 'goal' of the trip. YES! First 'discovery' (picture below)!
Discovery Note:
1. This knobbly sea star was probably about 10cm in length for each limb. About one time bigger than the juvenile knobbly we saw last time when we were on Semakau.

Maybe my luck wasn't that bad after all, i thought, so with my hopes higher, i moved on.

And shortly after, i came across the second 'discovery', a synaptid sea cucumber (picture below).
A closer look near its mouth (picture below).
Discovery Note:
1. It has no tube feet except for highly modified ones that form the oral tentacles.
2. It has a very thin, delicate body wall that feels sticky to touch. The stickiness is not due to mucus or other adhesive, but to other hundreds of tiny, anchor-shaped ossicles located in the skin.

We were really lucky to have a almost clear sky on the day. Because if it's clear, we will get to see the sunset! Here's the first of the set of sunset photos i took on the day (picture below).
As i continued to look around amongst an area of seagrass, i saw a stir of the sand nearby and a closer look proved to be the third 'discovery', a coastal horseshoe crab (picture below)Discovery Note:
1. Horseshoe crabs have known to 'roam' the earth since days even before the dinosaurs was around, so scientists calls them 'living fossils'.
2. Although they are called horseshoe crabs, they are not related to crabs. They are actually more related to spiders and scorpions.
3. There are two types of horseshoes crabs which we can find in Singapore, the mangrove one (circular tail) and the coastal one (the trianglar tail)
4. The tail is not venomous and is not used as a weapon. It is merely used as a lever to right itself if it is overturned. If you see an upside down horseshoe crab struggling with its tail waving around, do give it a helping hand. It will not hurt you.

5. The blood of the horseshoe crab is blue, as it is copper-based.
6. Their blood is able to clot easily when it detects bacteria, so their blood was harvested for these purposes until a team from NUS's department of Zoology has cloned a substance to replace using horseshoe crab's blood. Read more about it here.

And just not far away from what i saw the horseshoe crab was some round shapes on the sand. Oh, sand dollars. (picture below
) And this is fourth 'discovery'.Discovery Note:
1. Living sand dollars are coated in fine, harmless spines that made them very velvety.
2. The spines are movable and are used to dig into the sand or move around.
3. The dense layer of spines also helps to keep off sand and silt so there is a flow of oxygenated water across the body.

As the sun continued its descent down to the horizon, i continued my photo taking of its movement (picture below).
And as i went on walking around the seagrass area, i spot this mosaic crab (picture below), fifth 'discovery'.Discovery Note:
1. This is one of the most poisonous crab in Singapore.
2. Thus, I give the strongest advice not to eat this. =)

The beautiful sunset again (picture below).
As I rejoined the main group, CH cried out, 'Knobbly'. And i not wanting to miss another chance to see another knobbly went over and it was another knobbly sea star (picture below) which was similar in size to the one i saw earlier. What luck!Finally, a photo of the full moon from the shores we were at (picture below). PY commented at the sides that this didn't looked like we were on Singapore and i agreed totally. =)Lastly (really the last), it's thanks again everyone!

a) More about the trip on Wildfilms.
b) Check out the seahorse they saw on Colourful Clouds.
c) A very very tiny cowry on manta's blog.

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