Field experiment set-up

It was an awesome or terrible day, depending on how you look at it. We - Xue-Ping (research assistant), Shan-Hua (another PhD student), Wei-Jie (Dive guide) and I went to our field site to set-up the in-situ field experiment.

There are several goals on this trip :

1)  Cover half of each coral colonies (Acropora muricata) with transparent net. There are a total of three colonies. The hope of covering half of the coral colony is to dampen the water flow around it, but not affecting the light intensity too much. Of course, there is always a cut in light intensity when you cover the coral with a net. However, I did a preliminary test in the lab using a light meter, and the light was cut about 10% - 15% on an average, and there are still some peaks which are as high as the normal lighting conditions. Thus, I am willing to accept the small change in light intensity, knowing it shouldn't impact the coral too much with this minimal light intensity change.

Setting up the nets underwater is harder than it looks

2) Collect two samples of coral nubbins from each colonies, and will extract their mucus later in the lab. I am going to analyse the microbial communities in the mucus later on in Academia Sinica, Taipei

3) Collect surrounding reef water for analysing of microbial communities.

4) Get DivingPAM readings for the coral colonies. This reading tells the photosynthetic health of the coral, and I am using it as a indicator for coral stress. I hypotheses that the half of the coral within the net should experience higher stress than the other half which is not covered. This is due to the reduction in water flow (got to do with removal of waste, radical oxygen, transport of nutrients etc).

5) Shan-Hua is going to core a couple of coral colonies for her samples. She is examining the endolithic microbial communities in Isopora sp.

Well, it is a lot of work, but it does sound pretty simple. I mean some hammering, some manoeuvring of the nets around the corals, etc but it shouldn't be hard. I WAS WRONG! Well, Wei-Jie helped with all the hard work..hammering, drilling etc. I have to in charge of the nets, the reading of the DivingPAM etc. I was the only one who knew how to operate the DivingPAM, and thus it is my job. It wasn't a difficult job - point the optic fibre on the coral branch, wait for 5 secs, fired off a light source (from the DivingPAM), and read the value yield. I do not even need to record the values because it is automatically saved in the instrument, which I can retrieve later. However, there are a few "BUTS" -

1) I need to read the dark-adapted values, which means I can only use the DivingPAM during dusk hours. And since this is the first time, I also need to do another set of light-adapted values as a baseline. So I need to go once before the sunset to read the coral colonies. As a result, there was a lot of diving, 2 dives for DivingPAM readings, 2 dives for setting the nets up. And it was a chilling 23degC, and we were shivering!

2) For the reading on the DivingPAM, I need to ensure the values fall within a certain range before I fired off the light in the fibre optics. This means that for 9 readings on a single colony, I was staring at the small screen on the DivingPAM underwater for about 10 - 15mins. So it is like reading a book in a moving car - I got really SICK... and I throw up after every use of the DivingPAM!

Again, harder than it looks...especially when the current is going

Well, first day is over, and I got what I need for my samples...two more collection days to go!

All in a day's work

And now, for some surfing on the web...

Shan-Hua (left), Xue-Ping (right)