Collecting Data like Ecologists, Chasing Each Other like Seniors

One would assume that a group of students going on an Ecology field trip would find many different types of organisms in the Mangrove forests and along the Rocky shores. However, though there were indeed a lot more organisms outdoors, the ironic truth is, there was more life indoors along the hotel corridors and auditorium than anywhere else during the entire four-day weekend.

Mangrove forests

Heading to the Mangrove forests, my Green Turtles observed the Avicennia marinas, also known as the grey mangroves and the Rhizophora mangles, also known as the red mangroves. There were distinct abiotic differences between the two areas with different dominant mangrove species. We found that the grey mangrove area had higher air and water temperatures than the red mangrove area. It can be inferred that this is so because of the physical differences between the two mangrove species. Red mangroves are much taller than grey mangroves and have large, extensive roots and branches which often overlap and tangle with other red mangrove trees. As the structures of the red mangroves cover the sunlight and offer more shade, the light intensity decreases and cools the air temperature below. On the other hand, the grey mangroves grow upright, are much less extensive and cover very little space compared to the red mangroves. This allows for sunlight to pass through, causing the grey mangrove area to have a higher light intensity; which as a result leads to higher air temperatures.The same goes for the water temperature. The more the water is hit by light, the warmer it will become. It is also important to keep in mind that the grey mangroves were in immediately next to a river. This river had no extensive branches or large leaves offering shade and had direct sunlight hitting its surface. Meanwhile in the red mangrove area, water temperature was measured when the tides began to enter. Since the water is moving from one location into another, the water is exposed less to direct sunlight and are much cooler. From the differences between the light intensities as well as the temperatures of air and water between the two areas, it can be said that even whilst both species are seen as mangrove types, each mangrove type has its own distinguishable relationship to its environment.

The variations between the abiotic factors also show a potential possibility for the biotic factors to be just as variant. This was definitely the case since as I mentioned before, the grey mangroves were closer to the river. By being so close, the grey mangrove area had a chance of having marine organisms whilst the red mangrove area did not. The difference between the river and water flowing into the red mangrove area is that the river is always there regardless of the time of date whereas the tides come in usually during noon or even after. So predominantly in the red mangrove area, the soil is very damp due to the tides but stable and dry enough walked on. With having the river nearby, there were organisms such as guppies, periwinkles and waterstriders which were all present in the grey mangrove area but unidentified in the red. But organisms such as flies, mosquitoes and snails all known to be flexible and tolerant to harsh conditions and extreme conditions, were spotted in both mangrove communities. Lichens, fungi and algae were all seen growing among the soils, roots, barks and even branches within the two mangrove types. Another organism seen in both communities was the mud crab. Unfortunately, my group didn't see any of them in the grey mangrove area but saw plenty in the red. The only reason we knew there were mud crabs in the grey mangrove community was due to the other groups sharing what they had seen. We feel that the reason our group did not see these crabs was because the soil in the grey mangrove area was equally damp but sandier compared to the soil of the red mangrove area. From their names, it can be assumed that these mud crabs would most likely prefer damper soil, which is more similar to mud than to sand. Therefore, it could be hypothesized that perhaps the soil for the other groups in their line transect may have been damper than the soil in our line.
Clearly, the organisms inhabiting each of the mangrove communities are similar. However, the richness or abundance of each organism also need to be evaluated. To quantify the abundance within the two areas, we found the total number of organisms we spotted as a group. There was a total of 48 organisms counted in the red mangrove community and 77 in the grey mangrove community. These numbers are a result of using the transect line method in both of the communities. Clearly from our data, the grey mangroves are inhabited by a large population than the red mangroves. To be fair though, in my own personal experiment I found that the red mangroves had a higher biodiversity than the grey mangroves. But this was found through quadrat sampling. So in order for the data to be fully justified for a reliable and valid conclusion, it is essential to replicate the use of both methods to measure the richness and evenness of the organisms present in the ecological area.

Rocky shores
After a few hours of in the mangrove forests, we headed down to the Rocky shores to do a similar form of data collection. Here, we used quadrat sampling on a line transect, where 6 quadrats adjacent to each other along the line were used. The length of the line was 4.1 meters, tied to one pole in the water and one up on the rocks. The line was not horizontal since the rocks were at a higher elevation compared to the water, meaning that the line had an angle of elevation. Within the two poles were the 6 quadrats used for data collection. The first three quadrats were in the water entirely, while the fourth included water and surfaces of a rocks while the last two quadrats were entirely with casual tides flowing in. As our data was collected, we found that the water temperature was 27°C with a partially cloudy scenery. The wind was blowing in a northeastern direction and there were 27 tides which hit the rocks in one minute. Same as the mangrove forests, there are clear reasons to the distribution of organisms along the line transect depending on these specific abiotic factors.

First, we were able to identify two species of periwinkles along our line transect, the knobbly periwinkle and the rock periwinkle. We found that the knobbly periwinkle were more evenly distributed along our line than the rock periwinkles which were only found in quadrats 3, 4 and 5. After some external research, it was understood that the rock periwinkles usually wedge into crevices of rocks and are naturally known to be clumped together in one location. This explains why the knobbly periwinkles were more spread out. Rock periwinkles are most active at night or in cool/rainy days, which is a possible reason as to why they were found in the middle quadrats between the rocks and the tides. The tides are able to cool off the rocks, especially when it is 27°C. On the other hand, knobbly periwinkles are also usually found in the cracks between rocks. They have a rougher shell than the smooth shells of the rock periwinkles, thus enabling them to withstand higher temperatures and rougher tides. When they are up high on the rocks, their shells keep them cool. When they are in the lower areas, the shells protect them from the tides. They are usually dry throughout the day, so the medium light intensity as mentioned previously allows them to attach to the rocks without getting burnt. These characteristics are possible reasons as to why the knobbly periwinkles were found in all but the first quadrat. The first quadrat had no rock surfaces above the water which is a very likely reason as to why none of the two types of periwinkles were identified there.

While there is a difference in the distribution of the two periwinkles, there is a similarity between the distribution of the acorn barnacles and the knobbly periwinkles. Both of these organisms were identified in all but one quadrat. The acorn barnacles were not identified in the 6th quadrat, one which consisted only of rocks with little to no tide. This difference was caused most likely due to the fact that acorn barnacles are able to successfully attach to hard surfaces by excreting 'glue' through their cement glands - which the periwinkles do not have. The 'glue' is so strong it is common for the barnacle's shell to stay in place even after it is dead. Therefore, even with the tides or wind direction, the barnacles are able to hold their position without being dragged off. This explains why all of the acorn barnacles identified were all seen in the first 5 quadrats where the waves were clearly hitting on the rocks. Also, we found that these barnacles were clumped together just as the rock periwinkles. The reason for this is because barnacles have reproductive organs of both genders and having a community is an advantage for cross-fertilization, especially when fastened in one position. 

After a day of back straining work climbing through mangroves and bending over in the rock y shores to collect data like ecologists do, we headed back to the hotel. Physically, our bodies had faced a challenge but mentally, we were provided with a lot of new information. The variety of abiotic and biotic factors identified in the mangrove forests and the rocky shores demonstrate how each organism reacts according to the biotic factors present in their environment. This is ecology. And although it may have taken a huge amount of time to collect all of this data, as my Green Turtles group would say, slow and steady wins the race. With biology and fun so closely tied together by this one trip, we found that even after a long day of chasing mud crabs for a quick photo, we still had enough energy to keep our vigour as high as the red mangroves and chase after each other. So, if we were to sum up the fun and academic side of this trip, it could probably be done by the phrase:

Slow and steady wins the race, but wild and cheery starts the chase.