Dongting Lake Wetland Ecosystem Observation and Research Station (Dongting Lake Station for short), founded in 2007, is subordinate to the Institute of Subtropical Agroecology, Chinese Academy of Sciences, and is one of the long-term observation and research bases of Chinese Academy of Sciences in the middle and lower reaches of the Yangtze River. The station is based on the establishment, development and improvement of lake wetland ecosystem positioning observation research, providing CERN with long-term monitoring data support, and focusing on the study of watershed landscape evolution and ecological function response; Evolution of ecosystem structure and function driven by human and climate change; Degradation mechanism and restoration approach of wetland biodiversity; Mechanism of material transfer and transformation in lake wetlands; And the sustainable utilization of wetland resources in Dongting Lake, providing demonstration models and technologies for the positioning of wetland ecosystem service functions, ecosystem management, protection, restoration and reconstruction of alternative industries in the Dongting Lake basin.

In recent years, human activities have discharged a large amount of industrial wastewater and domestic sewage into lakes and other water bodies, resulting in excessive content of nitrogen, phosphorus and other plant nutrients, which greatly accelerating the eutrophication process of water bodies and causing serious "water blooms". Dongting Lake, located in Hunan Province, is one of the most important lakes connecting the Yangtze River in the middle and lower reaches of China. However, the total phosphorus content in the east of Dongting Lake is increasing explosively. The content of total phosphorus has exceeded the standard, which caused the rapid propagation of aquatic plankton, especially algae. Besides, the sharp decline of dissolved oxygen content in the water body and the death of fish and other organisms resulted in the eutrophication of Dongting Lake. We hope to make the recovery of phosphate in sewage or polluted water by biological means, as well as the release under artificially controlled conditions.

In order to test if our project is with the opportunity in practice, we’ ve visited Dongting Lake Station for Wetland Ecosystem Research of C.A.S. and communicated with the experts studying Dongting’s protection in August, 2022. By checking the real environmental condition, we could test and model P Pack in a more objective way. After communicating with the experts who worked in the station, he suggested us in order to perform a practical application of P Pack, the bacteria should be immobilized to get rid of the possibility of leakage. The experts also introduced the real situation of Dongting Lake to us, helping us establish a possible application condition. In addition, we've investigated the real place in Dongting Lake, which helped us about the engineering design. Genetic parts of the bacteria are induced by thermal signal instead of chemical inducer, which may be inconvenient during eutrophic water management. Investigation in Dongting Lake has inspired us about the management while choosing the inducing methods. Inducer such as IPTG and arabinose provides additional chemical components to eutrophic water, which may provides chemical pollution. This need take into consideration. The investigation in Dongting has also provided a chance to study the real condition of eutrophication in natural environment. We've also collected the lake water for part testing.

At eight o'clock that morning, our group drove to Dongting Lake Station and had a brief exchange with the expert of the base station to get a general understanding of the development history of the base station and the current water quality pollution situation of Dongting Lake. On the advice of the expert, we planned to go to the waters near the Six Gate for sampling first, then to the field sampling base of the station, and finally around Junshan Island for collection.

The waters of the Six Gate is below a large slope, which is covered with many kinds of weeds, and there are also sun-dried shells and conches on the roadside. There are a few egrets parked on the beach across the lake, but they are afraid of people and will fly away immediately when there were anything happened on our side. The view of the lake is very nice and the air is clean, with a kind of freshness and fragrance unique to nature. After enjoying the scenery at the lake for a while, our team leader put on gloves, scooped some in the lake water, filled the 50mL centrifuge tubes we brought over, then put them in a bag and packed them. We got in the car and left the place. This is the end of the water sample collection here.

Next, we were scheduled to go to the field sampling base, but we almost got lost because of the complicated terrain and many trails nearby. On the way, we also went to a local restaurant nearby to taste the specialties of Yueyang. Hunan is known as the "land of fish and rice", with its humid climate and rich produce, and the taste of fish is very delicious.

On the way to the base, the scenery of Dongting Lake is also very charming, with one island scattered in the middle of the lake, and a large piece of green growing on the mudflats, and a few small animals can be seen hiding in it when the wind blows past. At noon, the leisurely egrets would stop on the water to feed, and from afar, it was a scenic painting to heal the weary soul. On the way, we passed by a reed field and went through it to collect mud, but we didn't stop much because the ground was wet and soft.

Our project try not only to solve a exact problem, but try to deliver an idea of sustainable development. In fact, Hunan Province is faced with a contradiction. Our freshwater ecosystem suffers from eutrophication caused by phosphorus overdose. However, Hunan is one of the biggest area in China in rice production. Expansion of fields desires industrial products such as fertilizer that contains phosphate. And finally, the contradiction of human being should be solved by the ideas of human beings themselves, that’s why we treat sustainable development as a significant thought. We hope that P Pack could take the thought into some actions.