Bau (means "smelly" in Malay language) is known as a gold mining town in Kuching, Sarawak. Bau is popular for its two important historical events and two beautiful limestone caves which is the Fairy Cave and the Wind Cave. The Fairy Cave takes its name from a stalagmite structure at the entrance that is said to resemble a Chinese deity, meanwhile the Wind Cave was named after the constant cool breeze that blows throughout the cavern. In the Wind Cave, the visitors can take the chance to observe the swiftlets and bats that dwell within this large cave and in the same time, they are able relax besides a subterranean stream that runs through the cave.
This field trip was compulsory for all of the Year 1 students from the Resource Chemistry course. It was held on the March 3rd 2020. In this trip, students were assigned to survey three sites at Bau, Sarawak. However, due to raining, we were only able to survey the Blue Lake's area and the Wind Cave Nature Reserve.
Blue Lake
Tasik Biru (which means “blue lake” in Malay) is located at 5 minutes from Bau township. Tasik Biru is not a natural lake. It is the result of an open cast gold mining in that area. Its original name was Tai Parit (big drain in the Hakka dialect). The gold mine was operated by the Borneo Company from 1898 until it was flooded in 1921. Signboard have been put up at the lake side by the NREB warning the public against swimming, fishing, bathing or drinking the water from the lake as the water was suspected to contain high level of arsenic.
Lake ecosystems are made up of the physical, chemical and biological properties contained within these water bodies. Lakes may contain fresh or salt water. A lake ecosystem includes biotic factors such as plants, animals and micro-organisms, as well as abiotic factors such as physical and chemical interactions.
The important abiotic factors in lakes are the low salinity, temperature, sunlight and soil composition. The topmost layer of the lake is the warmest to support a host of life such as fish. Fish are the most well-known biotic factor in freshwater ecosystems. They may eat algae, aquatic plants, worms or smaller fish. The deeper we go through the lake, we will notices that the temperature drops. As we go deeper, we will also notices that the amount of sunlight receives by the water decreases. Hence, a shallower lake will have more diversity of plant and animal life, because the sunlight penetrates more of the water layers.
Wind Cave Nature Reserve
The Wind Cave Nature Reserve is located 5 km from the former gold mining settlement of Bau and 48 km from Kuching, Sarawak. Just half an hour’s drive from Kuching, Wind Cave at Bau meanders through a rocky outcrop on the banks of the Sarawak River. The Wind Cave (also known as Gua Angin) is believed to have get its name from the cooling breeze blowing continuously through the cave. Its smooth, tubular limestone cave formed during the Jurrassic-Cretaceous period, roughly 60 million years ago.
As we were walking to the cave, we were able to explore the flora and fauna there. As you can see in the pictures above, there are many epiphytes and vines that we were able to see closely and we also tried to recap back what we had learned in the class before about their roles in the ecosystem. An epiphyte is an organism that grows on the surface of a plant and derives its moisture and nutrients from the air, rain, water. They grow on plants and having their root structure off the ground instead of in the ground. Epiphytes play an important role in tropical rainforest diversity and productivity. Since epiphytes do not have roots in the ground, in order to survive, they form a dense root systems that have a large surface area which enable them to absorb rainfall. Many epiphytes such as orchids store water in their thick stems, meanwhile other epiphytes collect water in their leaves, enabling them to have a supply of water during dry periods of time.
Living in the canopy does giving epiphytes few advantages. First, epiphytes are able to get much more sunlight in the canopy than they would be able to get when living on the ground. Since they live on trees, the epiphyte does not have to use energy to reach high into the canopy from the forest floor and compete with trees and vines. The wind, insects and birds are also very important to most of the epiphytes. It is because the more organisms that come in contact with the epiphyte, the more likely that it will be pollinated and its seeds distributed. Living high in the tree canopies give a benefit to them in reproduction.
The Wind Cave’s has been gazetted as a nature reserve not just to protect the cave and its inhabitants, but also to conserve a number of rare species in the surrounding limestone forest. Twelve distinct species of snail have also evolved in the caves and the covering hill, each unique to its own limestone habitat. Black nest swiftlets can be seen and heard inside the cave, as well as 14 species of bat. The visitors can also see some of the 6.16 hectares of forest and rivers in the protected reserve surrounding the caves.
As we know, bats are nocturnal animals and caves have been long known to support large colonies of bats. This is because caves provide the kind of protected shelter in which bats can thrive. By hanging from the ceiling of a cave, bats are out of reach of most of their enemies. A special adaptation that allows bats to hang upside down for months without using any energy is the tendon from their talons which is connected to their upper body, not to a muscle. So when they hang, the weight of their body holds them in place and they can then drop straight into flight when they wake up.
Bats also are warm-blooded animals. Unlike other mammals, they let their internal temperature drops when they are resting, going into a state of decreased activity to conserve energy. Therefore, temperature in the cave is important to the bats especially during their hibernation as their body temperature will drop to the temperature of the cave. A cave offers an optimal temperature that bats need, allowing them to be comfortable without burning up too much energy. Besides, caves also provide optimal humidity that bats require and protects them from their enemies by hanging upside-down from the ceiling of a cave which offers a level of safety for bats.
One interesting fact about bats is they have the ability to create and hear noises that humans cannot hear. Bats use echolocation to locate food and avoid obstacles in the dark. To echolocate, bats send out sound waves from the mouth or nose. When the sound waves hits an object, they produce echoes. The sound waves bounce off of objects and back to the bat, which can then estimate the size and distance of the object. Each bat recognizes its own pulse reflections, or “voice,” and uses it to avoid objects and to identify food in the dark.
R e f l e c t i o n
As a responsible citizens, we need to protect our ecosystem and keeping them healthy. This is because ecosystem provides habitat to wild plants and animals which supports different food chains and food webs. It also regulates essential ecological processes and support many lives. Besides, ecosystem also helps in maintaining the flow of energy such as carbon cycle, oxygen cycle, nitrogen cycle and water cycle. Actually, by keeping ecosystem to be healthy, we also helping ourselves because a healthy ecosystem will help to clean our water, purify our air, maintain our soil, regulate the climate, recycle nutrients and provide us with food. This is called as ecosystem services. Ecosystem services are the benefits that human get from the nature. This field trip makes me able to see the real beauty of nature and it also make me feel terrible because we, human are destroying the ecosystem for money and power when the nature can survive without man but we, human cannot survive without nature. We contaminates the earth, pollutes the air and space and spoils the water. We are the one who cause the global warming and climate change. We are killing ourselves, aren't we?
I really enjoyed the field trip. We were not only come to visit or survey these places for fun but we also able to use our knowledge in this course to help us for a better understanding in what we had learnt in class. When I first saw the vines hanging from the trees, I already know that they were stranglers and Lianas and not as the woody vines that Tarzan used in the movie. I already know why they were growing rapidly up the tree trunk. They used the trees for support as they climb upwards towards the sunlight for survival.
This field trip does make me more understand the roles of biotic and abiotic factors in the ecosystem. As we know, ecosystems are influenced by both biotic and abiotic factors. From this field trip, I able to understand how abiotic factors directly affect biotic factors and if one of the factors is changed or removed, it can affect the whole ecosystem. I could say that abiotic factors are the most important because they affect directly how the organisms survive. In my opinion, everything in nature is reliant on each other. If one organism is removed, the entire ecosystem could suffer. This is why it is so important to protect the environment we share with every other living creature on this earth.
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