I, Sphagnum Moss, am almost 300 million years old and a great drinker!

If you have been to Dajiu Lake in Shennongjia, you will definitely be impressed by the power of nature. As the only subtropical and subalpine peat moss wetland in the world at 31° north latitude, Dajiu Lake has more than 1,000 hectares of water and is home to more than 1,000 species of animals and plants.

Among them, there is a lower plant that is smaller than one-tenth of our little fingernail, but plays a huge role. It is Sphagnum Peat.

Dajiu Lake

Image source: VEER Gallery

Part 1

The collaboration between peat moss and Dajiu Lake

Sphagnum moss is very small, with tongue-shaped leaves that are only 1.6-1.7 mm long and 1-1.4 mm wide. However, despite its small size, it is quite old. It appeared in the late Permian period of the Paleozoic Era, 250 million to 295 million years ago, which means it is nearly 300 million years old.

As a lower plant, peat moss has a relatively simple structure. It has no roots, stems, leaves, or vascular tissue, so it cannot absorb water from the soil through its roots.

Therefore, relying on its tenacious attitude towards life, peat moss has evolved the ability to obtain water through its leaves, which just makes it and Dajiu Lake Wetland complement each other.

Botanical Atlas of Sphagnum Moss

Image source: Reference 2

Dajiu Lake Wetland has unique climatic conditions, with annual precipitation reaching 1528.3 mm, more cloudy and foggy weather, and relative humidity greater than 80%, allowing peat moss to settle here.

However, the precipitation in Dajiu Lake is not evenly distributed throughout the year, but it does not flood in the rainy season and becomes dry in water-scarce years. This is due to the peat moss.

Because peat moss is really good at drinking water. How much can it drink? It can only absorb 20-25 times its own weight in water. When there is sufficient rain, peat moss continuously absorbs and stores water, and when the surrounding environment is dry, it releases the water.

In the process of continuously absorbing and releasing water, peat moss has nurtured the complete subalpine wetland ecosystem of Dajiu Lake.

Part 2

Why is peat moss so good at "drinking water"?

Do you want to know the secret of peat moss's strong ability to absorb water? Then you have to start with its leaves.

The leaves of peat moss are mainly composed of cellulose and contain a large number of hydrophilic chemical groups, which lays the foundation for the peat moss's water-loving nature.

The structure of its leaves is very clever, with the leaves shaped like a half gourd, like a scoop. There are many uneven protrusions and micropores on the surface of the leaves, which increase the roughness.

Therefore, with the dual blessing of hydrophilic properties and rough structure, peat moss exhibits the characteristics of a super hydrophilic surface for water absorption, allowing water droplets to be adsorbed in large quantities in the porous structure, just like a sponge.

The porous structure of peat moss leaves

Image source: cited from reference 2

If you think that you have solved all the mysteries of how peat moss absorbs water, you are wrong. Peat moss does not rely on the courageous tactics of a single soldier to win, but on collaboration.

On the leaves of peat moss, from the tip to the stem, there are cells of different sizes. The front cells are smaller, triangular or short and thick cylindrical, and there are interconnected water holes between the cells.

After the water is fully absorbed by the tip, it is transferred to the hollow cells in the middle and end through the water pores, and then to the stem.

The shape of the leaves of the sphagnum moss water scoop is also important for water absorption. When a drop of water spreads on the leaves, one end sticks to the pointed tip of the leaf and the other end sticks to the wide belly of the water scoop.

Due to the different radii at the two ends, the capillary effect on the water droplets is different, which will cause a pressure difference, and will push the water droplets to move spontaneously to the belly area of ​​the scoop with a larger contact area.

The water droplets are connected to the tip and the water scoop, and finally transferred to the stem.

Image source: Reference 2

It can be seen that even though peat moss only has small leaves, it also contains the water-absorbing ingenuity created by nature.

Some people may ask, what will happen to the peat moss if it doesn't rain in the Dajiu Lake area? Can it still absorb water? Hearing this, the peat moss smiled and said: Human, you know nothing about my ability.

The answer is that even a thin layer of mist peat moss can absorb water!

The essence of fog is some small water droplets at the micro-nano level. When peat moss encounters foggy weather, the super-hydrophilic rough surface will come in handy. These small droplets are captured on the surface, flow along the grooves and gaps between cells, and are slowly absorbed.

As the mist accumulates, a layer of water film will gradually form on the uneven surface of the blade. When the water film touches the tip of another blade, it transfers force between the leaves just like absorbing raindrops and transports it inside for storage.

Water-absorbing peat moss

Image source: CCTV

Part 3

To regulate humidity, scientists bring peat moss into homes

Peat moss relies on its strong water absorption capacity to release water through transpiration in a dry environment, becoming a natural humidifier for Dajiu Lake. And we can also enjoy the treatment of natural humidity control at home.

An important criterion for measuring the comfort of our living environment is the indoor relative humidity. When the humidity is low, it is easy to cause health and safety hazards; when the humidity is high, it is easy to breed mold; and a relative humidity environment of 40%-60% is a more comfortable and healthy range for the human body.

Green smart home system

Image source: veer

The humidity-regulating function of peat moss can be used to manufacture humidity-regulating building materials for interior decoration. When the indoor humidity is high, the humidity-regulating materials containing peat moss can absorb excess moisture, and when the indoor humidity decreases, it can release moisture into the room, thus maintaining the humidity at around 58%.

At the same time, humidity-control materials absorb heat and lower the temperature when releasing moisture, which also plays a role in maintaining indoor temperature to a certain extent.

The tiny peat moss and the vast Dajiu Lake have been interdependent, witnessing each other, and achieving each other in the 20,000-year historical changes of nature. This is the creation of nature's tolerance, which allows even the smallest creatures to find a place to live and participate in the legend of nature.

The development of modern technology may allow peat moss to not only nourish the ecosystem of Dajiu Lake, but also provide inspiration for us to design green and intelligent living systems that save energy and reduce carbon emissions.

References:

1. Mu Yanyan, Wu Qimei, Zhang Zhaohui, Ding Haifeng. Effects of morphological and structural characteristics of six sphagnum mosses on their water holding capacity［J］． Acta Botanica Sinica, 2022, 40(2): 250-258.

2. Chen Tianchi. Study on the superhydrophilic mechanism of peat moss[D]. China University of Mining and Technology, 2018.

3. Xiong Wei. Preparation, distribution pattern and environmental interpretation of the Dajiuhu Sphagnum Wetland in Shennongjia[D]. Hubei University, 2021.

4. Zhou Xia. Research on composite humidity-control materials for photocatalytic degradation of formaldehyde under natural light[D]. Nanchang University, 2021.

5. Hu Mingyu, Yan Sheng, Hu Yuqian. Study on the antifungal modification of peat moss/diatomite composite humidity control materials[J]. Functional Materials, 2021, 12(52): 12048-12054.

Produced by: Science Popularization China

Author: Vivian

Editor: Wang Tingting

Producer: China Science Expo

The article only represents the author's views and does not represent the position of China Science Expo

This article was first published in China Science Expo (kepubolan)

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