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Monday, 21 April 2014

Tasik Chini Fieldwork - Hydrology (part one)

Dr. Khairul, my academic advisor and also the coordinator for this subject.
We were warned that we had to use a lot of physical energy for this fieldwork. And it was undeniable. This was the only fieldwork that we would have the opportunity to do it on the speedboat, how exciting (although it could be better if we got the chance to dive, hehe)! I had been on speedboat before when going to Pulau Tuba near Langkawi and when watching fireflies in my home town, so this was not very new to me but it was still fun to be on a speedboat, wearing the brightly-coloured life jacket.

I had to sit far back so that the boat would not topple as everyone gathered at one side.
Sampling water on a boat which would sway left and right, up and down was quite difficult. We even had to balance the number of people occupying each side of the boat so that it did not over-turn and everyone ended up in the water. Besides, the sampling devices are very very heavy as weight has to be added to the device so that it can reach the depth we want. After collecting the sample, we had to pull the device up again with extra weight adding to it. Moreover, if we fail to collect the sample during the first try, we have to repeat the same procedure again and again with decreasing body strength each time we redo (skills are important and we need lots of practices). Furthermore, the situation can be worse if you have seasick (gonna leave this for your imagination, haha).

Meter tape with weight. This is used to measure the depth of the pond.
Handheld multiparameter meter which is very convenient as we had 
The Global Positioning System. We need it to mark our location where we do the sampling.
The turbidimeter which we use to measure how clear the water is.
In-situ measurement will be carried out whenever possible during fieldwork as the quality of sample collected might change without proper management. Parameters such as temperature, pH and dissolved oxygen should be measured in-situ as they change their quality pretty fast. Thanks for the invention of portable measurement devices that we do not have to do all the measurements in the laboratory, which means we just have to collect samples for the parameters that we don't have the equipment to measure them on the site. On site measurement is more accurate too!

Here is the reason why we need so much labour work when collecting samples of a pond. After measuring the depth of the pond, we had to take the water sample at the middle of the depth by using the similar Van Dorn water sampler we used before. It was very heavy. Besides collecting water sample, we collected the sediment of the pond using sediment core sampler too!

The Van Dorn water sampler. We had a really hard time trying to send the messenger to hit the switch (the black colour thingy on top) but failed. As we were the last group of the day and the sun was setting, the boatman who had watched some previous groups doing it lent us a helping hand. He did it only once and it was a success catch! (erm, catching pond water, haha)
The sediment core sampler with 20kg of weight added on top to make sure that it penetrates the sediment deep until the whole core is inserted into the bottom sediment. So basically we dropped something heavy into the water and pulled up something even heavier. 
The sediment core which is 1 m long. For the first upper 50cm of the sediment, it will be spliced 3cm each into 'slices' of sediment. For 50cm onwards, we splice it 5cm each. After that carry the whole thing to the laboratory we use radioactive plumbum-210 to measure the sedimentation rate of the pond. (for the case above, we will remove some of the water from the sediment core, leaving behind 2-3cm as medium)

This was the most challenging and chaotic fieldwork of this trip. I could not take much photos on the boat as I did not want to risk losing my phone among the brown brown water (ok it is actually because we did not have enough hands on the boat for all the works). How nice if we had more time to do this without the need to rush back on time. Taking the boat is fun, but kayaking can be even great but too bad we did not have extra time to do so (boohoo).

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