ζ··ζ°΄ζ‘Έι±Ό (Fish in troubled waters)

24 02 2008

Today, 4 days after we used syringes to poke holes in Thalassia hemprichii, we went back to collect the samples.

Sihui, Siling and I arrived early about 3.40pm when the tide was still very high. We thus proceeded to settle down at a bench and take a nap, while waiting for Mr Lim to come at 5pm.

However, even at 6pm, the tide was still very high, so we wandered about the higher parts of the beach (nearer the fence), and saw quite a few interesting organisms!

There were many of these sea slugs (Onchidium) on the sea wall, and Mr Lim is simply fascinated at how fast they can glide/slide/crawl over the rocks.

Fiddler crab!

Another crab whose ID we’re not sure of…
[edit: according to revetaw, this is probably a sesarmine crab. thanks loads to revetaw for telling us :D]

Si Ling also managed to spot a snapping shrimp (also known as pistol shrimp or alpheid shrimp),which was out of its hole for some reason or another, and got caught by us!

Mr Lim is infinitely jealous of us, as he spent much of his time trying to coax a shrimp out of its hole on thursday (but failed), while we managed to catch it in a minute! Snapping shrimps are fascinating creatures, they use their one oversized claw to stun their prey!

Meanwhile, Si Hui was looking at this pair of hermit crabs…

She was observing it for quite a while, and said they look gross…

We also saw this weird looking thing that we couldn’t identify… Can anyone help please? (:

And it seems like Labrador Park is quite a popular spot for photoshoots!


Finally, at about 7pm, the tide was low enough for us to identify our plot and we immediately started cutting the Thalassia. As the tide was about our ankle level, and there was still heaps and mountains of Bryopsis floating around, it was really difficult to search and find the sheath for cutting, and Si Hui and I were forced to feel around with our fingers (thus the name, which literally means groping about [for fish] in murky waters). Slowly, as the tide receded, we were able to see the bare patch on the ground with random bits of Thalassia left.

The two bricks marked out our plot.

Then, when we were about to leave as the sky got darker, Si Hui and I spotted this blue thing floating in the water. Thinking it was a piece of rubbish, I picked it up, intending to throw it away. To my surprise, there was a crab underneath!

The Leaf-Porter Crab (Neodorippe callida)! It thought that the piece of plastic floating around was a leaf, and so hid under it.

That rounded up our day, and we went home happily (having spent nearly 4 hours at Labrador Park!) πŸ˜€

Although this may be our last time coming down to officially conduct research, we sure hope to be able to make frequent visits down to our favourite park!(:


Lab Park again!

21 02 2008

We left for Labrador Park on Tuesday during school, and reached there while the tide was still quite high.

The first thing we noticed when we reached was that the whole beach was covered in the green algae (Bryopsis).

We heard from Mr Lim and later, Ms Yang Shu Fen and Ms Siti, that these were seasonal though, so we weren’t particularly worried, although it did make the whole shore look dirty, unwelcoming and the water really turbid.

We also noticed that the construction works has been completed, as the barrier has been taken down. Another thing that our group is interested in is how the construction works could have affected the water quality at Labrador Park, so perhaps after the next group takes over us, they would notice a new trend!

As the tide was still quite high and Ms Siti and Ms Shu Fen hadn’t arrived, we started exploring the shore. We saw a small Moon crab

and some Fiddler crabs, as well as a little catfish.

Once the tide was reasonably low, the 6 of us (Si Hui, Si Ling, Mr Lim, Ms Siti, Ms Shu Fen and I) started our monitoring. Due to the excess Bryopsis floating about all over the place, it was really difficult for us to estimate the percentage cover of seagrasses. (Almost everything was covered under seaweed!) However, we still managed to complete our 33 random quadrats, and Ms Shu Fen and Ms Siti even spotted the Thalassia flower, which we heard was really rare!

It was also the flowering season for Enhalus, and Mr Lim spotted their flowers, although it hadn’t bloomed yet.

The Enhalus is the only species of seagrasses whose flowers have to be fertilised out of water; all other seagrasses complete their entire life cycle under water. “Seagrasses are so cool yeah!”

After monitoring, we punched holes in a little plot of Thalassia. This time, as we neglected to bring raffia and tent pegs, we improvised with chopsticks and bricks! With everyone except Mr Lim helping, the job was soon done, and as we left for the shore, we saw this huge catfish!

It was stranded by the receding tide and was hiding, when we ungraciously intruded into its presence and started snapping shots of it. It probably felt like a celebrity xP

We also saw markings in the sand which Ms Siti says looks like those made by Brittle Stars, although we didn’t see any 😦

Thus concludes our group’s last monitoring session at Labrador Park 😦 We will still continue coming down whenever we are free though, we are too attached to Lab Park! We will be going down again today during our RS block, just to look see and as Mr Lim says, picnic! (:

Special thanks to Ms Siti and Ms Shu Fen for coming down to help us!

Lab session:Follow up on “measuring Thalassia growth”

25 06 2007

Thanks to Ms Siti and her friends who helped us ‘collect’ seagrass with the holes poked through them, we were able to follow up on our tests to measure seagrass growth when we returned from our various overseas trips. πŸ˜€ So today, we gathered in the Biology lab to study the growth of the seagrass.

Unfortunately, we realised that some of the sheaths had dropped off and there were singular leaf blades (most likely separated in the process of transportation). We were rather at a loss as to how to measure, since if there were no sheaths, we couldn’t find the hole in the sheath to measure from to track the growth. Thank goodness Ms Siti was there and suggested an alternative – we would measure 2 cm from the bottom of the seagrass for uniformity. And thus we began.

We measured the distance between the holes (for most, the hole in the sheath was imagined to be present 2cm above the bottom of the seagrass) as the growth, and the length and width of each leaf blade in each thalassia plant and dutifully recorded everything down.

We were done after a few hours πŸ™‚ and actually, it was mostly uneventful, aside from one very sleepy person who kept reading off the wrong dimensions on the ruler, one very high person who commented oddly that measurement was more effective with wet sticky seagrass (“Because the seagrass will Stick to the Ruler!!!”) and two other rather quiet people including Ms Siti. (:

Stay tuned for pictures and further posts!!

measuring Thalassia growth

16 06 2007

Today, we went down to Labrador to begin the test to measure Thalassia growth. The plan was for each of us to be armed with a .22 hypodermic needle, to be used to poke a small but still visible hole in the sheaths of the seagrass in a designated patch. After a few days, we’d return to the same small patch and gather(aka dig out and collect) some of the seagrass from that patch. By measuring the distance between the hole in the sheath and the hole in the seagrass leaves, we would be able to track the average growth of the seagrass.
And so we began by choosing a patch of seagrass. The tide that day was very low and we quickly chose a small patch that was neither too overgrown nor too bare- just average. On the patch, we measured a square about the size of a quadrat and pegged tent pegs into the four corners. After tying raffia string to the tent pegs to mark out the square more clearly, we used a mallet to pound and embed the tent pegs into the ground.
Finally, we began the tedious job of poking the holes into the thalassia seagrass. It wasn’t as easy as expected- we had to dig into the sand to find the sheaths to poke into with the needles, and it was numbing to keep squatting. Thankfully, with our concerted efforts, we were satisfied and decided that we had poked holes in enough seagrass. Our target was 50 leaf sheaths in total so that even if some of the seagrass had died or been eaten or even mysteriously disappeared, we’d still have enough to do our calculations with.
Settled, we happily went home! Thank you Ms Siti for always coming to help out! And sorry if the explanations aren’t very clear, photos will be up soon for better understanding!

Because our entire team (including Mr Lim) would be leaving for an expedition in Hong Kong from the 18th to the 22nd, Ms Siti helped us collect the seagrass samples that we needed before they died. Thank you Ms Siti again! πŸ˜€
This plan was suggested by Dr Len McKenzie when he was in Singapore for the Seagrass Workshop. The sheath is where each leaf blade in the plant grows from, so when we poked a hole in the sheath, the hole would go through all the leaves of the thalassia, and this is what made our plan feasible.