One the most
awesome highlight of this year is the IB Biology Year Two HL field trip. I
recalled us packing and loading up to two buses and heading off to Pranburi on
the September 20, 2012. In addition to having memorable times there, we also
conducted two experiments on the ecology of the rocky shore area of the beach
and the ecology of the mangrove forests. We visited the mangrove forest near
the Pranburi river and the man made rocky shore of the sandy shore beach next
to the ocean. Thus, these two investigations will be explored in the following
blogs.
Mangrove Investigation
During our time
at the mangrove forest, our group was divided into two in order to investigate
two areas. The first area, which is away from the river, will be referred as
mangrove A and the second area, which is situated next to the Pranburi river,
will be referred as mangrove B. While
mangrove A was surrounded by mostly grey and red mangroves, mangrove B was
surrounded mainly by yellow mangroves. We investigated both the abiotic,
including temperature, pH levels, water quality, turbidity, dissolved oxygen,
water dept, salinity, light intensity, and substrate, and biotic factors,
pertaining to the biodiversity, for each site. The results were then recorded
and compared for further processing. To determine the biodiversity of each
area, we used the Simpson’s Diversity Index and the observed number of
organisms present per species. Although the data in mangrove A was collected
via a restricted single 1 meter by 1 meter quadrat, the data in mangrove B was
collected using a perpendicular transect that ran perpendicular to the river
and is about one meter of width and 10 meters of length.
Even though this
is not the first time I visited a mangrove forest, I am nevertheless amazed by
it. The scenery of a beautiful mangrove forest filled with astonishing
biodiversity stunned me. From what Sea, our expertise tour guide said, I learnt
some of the mangrove fun facts including its salty texture, different species
and its quality as valuable nursery areas for juvenile fish and crustaceans. Our “Red Crabs” groups, led by our
Ultimate Red Crab Queen Mendy, was divided into two groups, the R-1 and R-2
groups. Each group of 6 members collect their own data and thus two sets of
data per site are represented and conclusions are drawn as shown below.
Table
1: The shows the abiotic factors of mangrove A and mangrove B. These factors
include air and water temperature, dissolved oxygen levels, pH levels,
salinity, substrate observed, water quality, turbidity, dept of water and light
intensity.
Table
2: Shows the biotic factors in mangrove A and B, in which represent the species
presented and the abundance of each species in two sites.
Figure 1: comparing species of abundance in areas mangrove A
and mangrove B using graphical displays of the numbers of each species present
at each site.
With this data and using the Simpson’s Diversity index
formula where diversity (D) = [N(N-1)/∑ [ n(n-1)] with N as the total number of
organisms and n as the number of organisms of a particular species, the
biodiversity of each site is calculated. The larger the diversity or the D
value, the more diverse. Using the data from our data collection for the
abundance of species, the diversity for site A is 3.88 while the diversity for
site B is 1.56. Therefore, it can be concluded that there is more biodiversity
in site A, or areas away from the river, than site B, or the areas next to the
river. However, it should be noted that the yellow mangroves are smaller
species that live next to each other while the red mangroves live further away
due to its sport stilt roots. This could contribute to the less amount of
mangroves per quadrat in mangrove site A.
Comparing the abiotic factors, it is shown that mangrove A
had higher air temperature and turbidity when compared to mangrove B. The soil
is also muddier in mangrove A while mangrove B is sandier. Nevertheless,
mangrove B had higher water temperature, dissolved oxygen, pH, salinity, and
substrates observed. Both mangrove sites had low light intensity, mostly due to
the tall mangroves blocking the sunlight. Although mangrove B has more dissolved
oxygen and thus more nutrients than mangrove A, site B attract lesser organisms
than site A. This may be a result of the sandy, dry texture of the soil in
mangrove B. More over, mangrove A contained organisms, including crabs, fish
and tapeworms that are adapted to saline and submerged surroundings. From these information’s, I therefore
learnt that even though the mangrove areas seemed harsh due to the inconstant
tides, there are huge biodiversities due to its abilities to provide shelters.
Rocky Shore Investigation:
The rocky shore we investigated is actually man made
structures that protrude into the ocean. Using a perpendicular transect, we
observed the abundance of organisms as we went deeper into the ocean. We
calculated the slope of the rocky shoreline. The quadrats that are 0.5 meter by
0.5 meter were placed contiguous to each other from the lowest pole to the
highest one. The number of organisms was recorded per each quadrat. A tape
measure was used to find out the total distance between poles and the distance
perpendicular to the poles. In addition, we also measure the abiotic factors,
including air and water temperature, wave frequency, aspect, light intensity,
and wind direction.
Table 3: shows the abiotic factors of the rocky shore,
indicating the air and water temperature, wave frequency, aspect, light
intensity, and wind direction.
Table 4: shows biotic factors at rocky shore, indicating the abundance
of each species per quadrat
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Species
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Figure 2: shows a kite diagram of species abundance, indicating the
abundance of each species in the investigated rocky shoreline, having the first
quadrat most far away into the ocean and the sixth quadrate out of water.
According to the kite diagram pertaining to the data collected, the
abundance of acorn barnacles, limpets, knobbed periwinkles and the abundance of
rock periwinkles increased as the area invested is closer into the ocean. There
are nevertless optimal locations. For example, the optimal location for acorn
barnacles is in the 5th quadrat while the optimal location for rock
periwinkles are in the third quadrat. There are no optimal location according
to the observed data for limpets and knobbed periwinkles. However, if more
observations were made in different areas, we might be able to find the optimal
location for these organisms since our transect area does not cover all the
rocky shore.
Here, other than learning that rocky shores (even though it’s man
made) is beautiful and awesome, I learned that organisms are adapted in various
places! Okay.. maybe this knowledge isn’t that NEW, but it’s still a cool fact
worth mentioning. I just want to conclude that this biology trip is a highlight
of this entire year. I don’t think any supposedly education fieldtrip can top
this one.
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