Hainan Ding’an volcano cold spring in tourism season

_st place in Biotope Aquarium Design Contest 2022

Volume of your aquarium: 320 L

Dimensions of your aquarium: 100×80×40 cm

List of fishes: Unionidae, Rasbora steineri, Rhodeus ocellatus, Puntius filamentosus, Puntius semifasciolatus

List of plants: Sagittaria subulata (L.) Buchenau, Nymphoides peltatum (Gmel.) O.Kuntze, Cyperus malaccensis, Alisma plantago-aquatica Linn, Cyperus helferi

Description of Decorations and Substrate: The underwater scenery during this period is very beautiful, just like a natural aquarium. I use Nymphoides peltatum(Gmel.)O.Kuntze inside of Ottelia cordata ，and the water from the river gives a more original effect to the fish tank. The Nymphoides peltatum(Gmel.)O.Kuntze is also distributed locally in Hainan. It grows very luxuriantly and blooms several times. Therefore, manual intervention reduces some quantities to ensure visual effect. The lower Sagittaria subulata (L.) Buchenau grows wantonly and paves a road at the bottom of the pool, which is similar to the visual effect of the habitat. The yellow sand like the habitat is selected as the bottom sand, which is more original. During the growth of plants, some black organic matter is accumulated at the bottom of the water, making the fish tank look closer to the real effect. The local volcanic rocks are more precious. The stream stones in the streams are selected as the main scenery, and the blue background paper is used with the wide cylinder to create a spacious vision.
The choice of fish is Puntius semifasciolatus,Rhodeus ocellatus ，Rasbora steineri and Puntius filamentoand.all of which are some fish in the cold spring. The Puntius filamentosus is added to highlight the changes in the cold spring. The environment is deteriorating and invasive organisms appear. There are still a lot of Puntius semifasciolatus and Rhodeus ocellatus.

Description of Equipment: Odyssey water grass lamp50w, Trickle box

Water Parameters: Temperature: 23 ~ 25 ℃, Hardness: 5-10dgh, ph：6.3

Additional Info:

Aquarium video::

https://b23.tv/Kmnwsr4

Description of the Area Surrounding the Biotope: Jiuwentang Village is the distribution area of late Pleistocene volcanic rocks, which erupted more than 10,000 years ago to form volcanic platform landform. The volcano is bare and the road is rugged.
The edge of volcanic platform is a steep slope with a height difference of about 10m and a certain slope, which is formed by piling volcanic blocks and becomes the landscape belt of volcanic platform front. Layered volcanic peat is buried in the lower part of it, which is formed by burying the swamp by volcanic lava flow. The peat is gray-black and thin in thickness. With Daotiangou as the boundary and the Middle Pleistocene volcanic rock distribution area on the east, it was formed more than 700,000 years ago, and the surface layer has weathered into laterite, forming two completely different landscapes.
In the exposed areas of volcanic rocks in Hanlin, Longhe, Lingkou and Longmen Town, Ding ‘an, cracks and holes in volcanic rocks are developed with poor continuity. Coupled with the lush vegetation, the water temperature of groundwater supplied by rainfall infiltration is not easy to change, and the original rainfall water temperature is retained. According to the naming standard of mineral springs, mineral springs with water temperature higher than 32 degrees Celsius are “hot springs”, while those with water temperature lower than 25 degrees Celsius are “cold springs”. In tropical areas like Hainan Island, the groundwater temperature is generally 27℃, while in Jiuwentang area, the groundwater temperature is less than 25℃, which is a new discovery of groundwater temperature. Volcanic cold springs are formed by discharging at the edge of volcanic platform. Jiuwentang Village, Longmen Town, is a cold spring with the largest amount of volcanic rocks in Hainan. There are more than 10 springs, with a daily self-discharge of 40,000 cubic meters, which is the largest volcanic cold spring in China.
Jiuwentang volcano cold spring water is colorless, odorless, clear and transparent, and the perennial water temperature is 23℃ ~ 25℃.

Description of the Underwater Landscape of the Biotope: In Ding’an country , Hainan Island, there is a crater formed hundreds of thousands of years ago. Here is a cold spring with the largest flow in China. At the same time, it is also a famous tourist attraction: Ding’an cold spring. The water in the cold spring is clear and shallow, with a temperature of 23 ~ 25 degrees throughout the year. There are national protected plants,Ottelia cordata.And the Eichhornia crassipes (Mart.) Solms and Puntius filamentosus invaded by tourism development. There are a large number of native fish, such as Puntius semifasciolatus,Rhodeus ocellatus ，Rasbora steineri and Puntius filamentoand and some unknown Gobiidae .At the same time, there are plants such as Ottelia cordata and Cyperus malaccensis .The spring water is slightly blue. There are many volcanic rocks around it. It is a natural seat. The water temperature is cool.

Description of the Habitat Parameters: water is transparent，PH5.3，ph：6.0－6.5

List of Fishes and Invertebrates Occurring in the Nature Biotope: Unionidae
Rasbora steineri
Rhodeus ocellatus
Puntius filamentosus
Puntius semifasciolatus
Oreochromis mossambicus
Cyprinus carpio

List of Plants Found in the Nature Biotope: Sagittaria subulata (L.) Buchenau
Nymphoides peltatum(Gmel.)O.Kuntze
Cyperus malaccensis
Alisma plantago-aquatica Linn
Ottelia cordata

Threats to the Ecology of the Biotope: Countless tourists come here to play in the water every year, which also leads to the deterioration of the environment every year.Brought many exotic invasive fish such as tilapia and Puntius filamentosus

Sources of Information:
Hydrochemical Characteristics and Genesis Analysis of Basalt Spring Water in Lei Qiong Area
Dingan county lengquan travel magazine
Internet video

Name: Gaachi嘉辞
Country: China
Place: Guangzhou
Email: 2384258935@qq.com
Mailing Address: Row 3 6805，Baiyun Fort Garden，Baiyun District, Guangzhou，China 中国广东省广州市白云区永泰白云堡豪苑3排6805 telephone：13302212022
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