Hi everyone, Shalom Aleichem!
Good morning GanSist everyone! 
Welcome back to the Nusantara Series, a series that invites us to explore Indonesia from various points of view, starting from culture, local wisdom, history, tourist attractions, to natural phenomena that have high scientific value. In the previous series, we got to know the uniqueness of Kalimantan Batik which is full of Dayak cultural philosophy. This time, we are still on Kalimantan Island, but will visit a natural destination which is often referred to as one of the most unique lakes in Indonesia, namely Labuan Cermin Lake in Biduk-Biduk District, Berau Regency, East Kalimantan Province.
At first glance, Labuan Cermin Lake looks like an ordinary lake with very clear water. However, when researchers began to study its characteristics, they discovered various phenomena that made this lake different from most other lakes. In fact, hydrologists and ecologists have made this area a research location because it has a very unique water system.
The name “Labuan Cermin” itself is not without reason. The water is so clear that the bottom of the lake can be seen very clearly, as if one were looking into a giant mirror. This clarity is combined with natural phenomena that are rarely found in other places, making Labuan Cermin Lake one of Indonesia’s natural tourism assets.
So, what are the interesting facts behind the beauty of this lake?
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1. The water is so clear that the bottom of the lake looks like a mirror
The first uniqueness of course comes from the clarity of the water.
In contrast to many other lakes which appear greenish or cloudy due to sediment, the water of Lake Labuan Cermin has a very high level of clarity. In clear weather conditions, tourists can see the bottom of the lake very clearly even though the depth reaches several meters.
This clarity is influenced by environmental conditions that are still relatively well maintained, the lack of suspended particles in the water, as well as the geological character of the surrounding karst area which acts as a natural filter for ground water. As a result, the surface of the lake is able to reflect the shadows of the trees and sky so clearly that it looks like a mirror.
This phenomenon is not only visually interesting, but also shows the importance of maintaining the quality of the environment around the lake area.
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2. This lake is nicknamed “Lake of Two Flavors”
One of the most famous facts about Labuan Cermin is its nickname Lake of Two Flavors.
This nickname arose because the lake has two layers of water with different characters. The upper water layer is fresh water that comes from springs and land water flows. Meanwhile, the lower layer contains brackish to salty water which is influenced by sea water through an underground system connected to the coastal area.
Due to the difference in density, the two layers do not easily mix completely, forming a phenomenon known as water stratification. As a result, someone who dives can feel the change in the character of the water when it moves from the top layer to the bottom layer.
This kind of phenomenon is quite rare and is one of the main attractions of Labuan Cermin Lake.
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3. Hosts a Very Unique Ecosystem
This is the most curious fact.
Because it has two layers of water with different levels of salinity, the organisms that live in Lake Labuan Cermin also show interesting characters. Several types of plankton, fish and aquatic organisms are able to adapt to these unusual environmental conditions.
Research on plankton community structure shows that the physical and chemical parameters of the waters in Labuan Cermin have certain variations, such as temperature, salinity, pH and dissolved solids content. These variations influence the types of organisms that are able to survive in the lake.
For scientists, these conditions make Labuan Cermin a natural laboratory for studying the relationship between water quality, stratification and the life of aquatic organisms.
For tourists, this uniqueness may not be immediately visible. However, behind the calm waters are hidden very complex ecological processes.
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4. Its beauty must be maintained through sustainable tourism
The beauty of Lake Labuan Cermin brings economic benefits to the surrounding community through the tourism sector. However, more tourists also mean greater challenges in preserving the area.
Various studies regarding the development of Labuan Cermin emphasize the importance of conservation-based management. Construction of tourist facilities must be carried out without damaging water quality, surrounding vegetation, or the balance of the lake ecosystem. Apart from that, educating tourists regarding the prohibition of throwing rubbish, using products that can pollute water, and the importance of protecting karst areas is an inseparable part of conservation efforts.
With the right approach, Lake Labuan Cermin can remain a leading tourist destination as well as a conservation area with scientific value.
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CLOSURE
Labuan Cermin Lake proves that Indonesia has many natural wonders that are not only beautiful to look at, but also interesting to study scientifically. The extraordinary clarity of the water, the existence of two layers of water with different characteristics, a unique ecosystem, and the importance of conservation-based management make this lake different from most lakes in Indonesia.
Through the Nusantara Series, we learn again that the richness of the archipelago is not only in the form of culture and history, but also natural phenomena that can broaden our insight into science. Labuan Cermin Lake teaches that nature holds many secrets that can only be understood through a combination of curiosity, scientific research and concern for the environment.
Hopefully more and more Indonesians will know about, visit responsibly, and take part in protecting Labuan Cermin Lake. Because, natural beauty is not just a legacy from previous generations, but rather a gift that we must protect for future generations.
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SOURCE
Arum, ES, Hariani, N., & Hendra, M. (2018). Surface plankton community structure in Labuan Cermin Lake, Biduk-Biduk District, Berau Regency. Journal of Mathematics and Science Education, 9(1).
Fadhlillah, M. A. (2019). Directions for developing the Labuan Cermin Dua Rasa Lake tourist area in Berau Regency. Thesis. Kalimantan Institute of Technology.
Muzakki, H., & Zainurrosalamia, S. (2025). The influence of facilities, location and destination image on tourist interest in the Lake Dua Rasa Labuan Cermin tourist attraction. TOBA: Journal of Tourism, Hospitality, and Destination, 4(1)18-26.
Sari, N. A. (2025). Development of the Dua Rasa Labuan Cermin Lake tourist attraction in Biduk-Biduk Village, Berau Regency. Faculty of Social and Political Sciences, Mulawarman University.
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