monitoring session on 22 April

22 04 2007

On the 22nd April, our group met up once again for a monitoring session at Labrador Park. Yup, at 7am, we were at the Park waiting for the tide to recede and for our mentor, Mr Lim and our other group member, Jocelyne (whom we later found out was not coming) to turn up. When we finally started at around 7.30, the tide was extremely low, and was even receding, which was good for our monitoring, as we could actually see some of the seagrass that are generally submerged in the water clearly. Sometimes, certain areas of the seagrass patch are completely submerged by the slightly murky water, so we cannot observe things like the percent coverage of the seagrass in the quadrat. So naturally, our spirits were rather high, and efficiency level went up!

We started out by walking around the seagrass plot, and Mr Lim took the GPS readings so we would be able to map out the plot’s shape and area, so that we can observe how much the area occupied by the seagrass has increased or decreased the next time we go for a monitoring session. Next, we did the monitoring of one of the smaller plots and did 6 quadrats there. We then moved on to the bigger plot, of which we managed to complete 33 quadrats, in around 1 and a half hour, due to the nice weather, high spirits and efficiency level. It was such a pity that Jocelyne could not make it, but Si Hui and I had a lot of fun throwing quadrats randomly in the seagrass patch and examining it by filling up the datasheet, which included details like the type of sediment, photograph number, percentage of seagrass coverage, percentage of seagrass species composition, canopy height, and the percentage covered by epiphytes and algae. As I had to take the canopy height of the thalassia (by measuring the height of 3 random seagrasses, and finding the average of the three) besides jotting down all the information that Si Hui called out, and we could not gather both pieces of information from the same quadrat at the same time, because the clipboard I was using to measure the canopy height obstructed her view of the quadrat. we decided that after getting the canopy height of the first quadrat, I would immediately move on to the next quadrat to measure the canopy height there, while Si Hui would concentrate on observing the percentages, etc and move on to the quadrat that I would have by then finished measuring. I would then record what she said on the datasheets. In this way, we could do both simultaneously, and as we had only two quadrats to work with, we were motivated to work faster.

We noted that next time, it would be good to be better prepared, for example, bring extras of everything, such as foolscap paper, and rulers. We managed to improvise, though, despite not having rulers: we used the sides of the clipboard to measure the canopy height.

Along the way, we saw many interesting creatures, as usual, especially a lot of algae e.g. the bubble algae (not the scientific name, a layman term).  This particular trip to Labrador park was a very enjoyable experience for all of us, because we managed to get a lot of information, and we ended with high spirits, despite having to rush off for another activity soon after.





monitoring session on 7th april

7 04 2007

Early in the morning at 7am, we gathered at the pavilion next to the beach. We were going to conduct our first monitoring session!! Ms Yang and Ms Lim,both of whom work at National Parks (NParks) and are also part of teamseagrass, came down to help us.

However, the gate to the beach was only opened at 730am, so we started late and had to make sure we were quick so we could get everything done. When we finally got started, we realised that the tide was coming in, instead of being low tide as it was supposed to be. Teamseagrass, who went to sentosa the next day to monitor the seagrasses there, also experienced the extraordinary higher tide than usual, and are most concerned. Hopefully the effects of global warming will not be felt so soon…

We were going to try out a new monitoring method, where we would walk on the edges of the Thalassia hemprichii patch (as it is the biggest) and track the GPS coordinates every few steps. The previous method of 100 by 25 was deemed ineffective after a chat with the leader of seagrasswatch, Len Mckenzie. It was not a good method for monitoring as the patches of seagrass found here is mostly quite small and by using that method, we would have a skewed idea of the distribution of seagrass here.

However, as much as we wanted to start our actual monitoring, the tide was too high  and the water was too murky for us to see the edges of the thalassia patch which was further from the beach. The smaller patch of thalassia which was nearer to the beach(yep, we found 2 thalassia patches that day(: instead of just one!) thankfully, was still visible and we quickly tracked the location of the patch and measured the percent coverage before all was lost to the tide.

While we were measuring the percent coverage, Ms Yang and Ms Lim found a little hermit crab! We found out that when going for monitoring sessions, it is always good to bring a container, a pair of chopstick and a fork along so we can poke around with the chopstick, dig the soil with the fork and place organisms found (like the hermit crab) in the container to take a closer look! After we looked at the hermit crab upclose, we let the little creature back into its natural environment and carried on with our work(: We should never bully the little creatures which live here and bring them home with us!

After we finished our monitoring of that little patch, we decided that we should bring home some specimens of Thalassia hemprichii, Halophila ovalis and common macroalgae to put under the microscope and learn more about the differences between algae and seagrass! This was for learning purposes, therefore it is justified to take one specimen of each(:

All in all, it was a fairly good monitoring session despite the tide, as we learnt how to do a real monitoring session and will be able to do our next one properly in June.





2nd Recce at Labrador Park

1 04 2007

On the 17th March 2007, our group met up with people from teamseagrass for our second recce at Labrador Park. This time, we were going to test and find out which method to check for seagrass population density in specific areas would be the most effective.

 

Usually for monitoring, a horizontal transect line is laid out for 50m, and a vertical one which starts at the start point of the horizontal transect line is laid out for another 50m. GPS readings are taken at the start and end points of the transect lines, so we can find the same spot again on another day. A quadrat (a square-shaped border made of pipes, which have holes drilled into them and string passing through, holes, and basically looks something like a square grid) is then laid out at every 5m on the vertical scale. Based on a data sheet for the seagrass percent cover standards, we can estimate the percentage (amount) of seagrass there is in each quadrat.

 

The methods that we were considering were the random band method, 100m by 25m, or 50m by 50m. The random band method involves laying out transect lines as well, but instead of laying down quadrats at every 5m, the quadrats are thrown randomly around areas where there are seagrass patches. We decided not to use it, for it might leave us with skewed data. Instead, we debated over whether the 100m by 25m, or the 50m by 50 would be more feasible, but our questions were resolved when we laid out the transect lines. The seagrass patch mostly ended around the 50m mark, so it would not be very feasible to lay out the transects until the 100m mark.

 

Using the surroundings to help us benchmark the area, e.g. a pillar for the 25m mark, we made it easier to identify the area if there was a need to. At every 5m, we also took down notes of what was in the surrounding area, for example, rocks, halophila ovalis, colonial anemone, etc. This would help us to identify what were the factors that affected the presence of seagrass in the area.

 

Along the way, we had a lot of fun studying the many marine creatures that we saw and learning what they were called. For example, we saw the colourful Velcro crab, which covered itself with different types of algae as a form of camouflage, making it more difficult to spot. We also spotted other things like a nudibranch (a sea slug), a red egg crab, hairy crab, and more! We eagerly look forward to our next session at Labrador Park! (: