Tracking anthropogenic change in northeastern China
It’s another hot day in Nanjing, the ancient capital of several Chinese dynasties. And not just hot, but humid. It’s like stepping into a tepid swamp every time we leave the NIGLAS office. So Anna and I, postdocs on the P³ project, are happy to be packing our bags and boarding a flight to northeastern China for our first fieldwork foray.
Despite travelling over 1,500 km’s north to the city of Harbin, host of the world-famous ice festival during its -30°C winter, we have not managed to escape the summer heat. We pack all the boats, corers and field gear into our oversized van and hit the road to head further north. The crew play round after round of cards during the drive however the rules are beyond Anna and I who instead watch the fields of maize and rice roll past. We are heading towards Wudalianchi, meaning “Five connected pools”. The geo-park contains 14 volcanoes and is one of the youngest volcanic fields in mainland Asia. The most recent eruption occurred in 1720, forming two impressive cones that rise from the plains. The 5 lakes were created when the erupting lava dammed and divided the original river system and we will be investigating them with Dr. Kunshan Bao as part of his ongoing research into anthropogenic impacts on wetlands in northeastern China.
We are up early and head out to our first site to beat the wind, heat and tourists. Anna and I are excited to see our first Chinese wetlands, and the Wudalianchi lakes do not disappoint. They are huge freshwater systems (up to 700 ha) which are a popular tourist destination. The lakes are also stocked with fish and we see many early morning fishermen out on the lakes. The wetlands are not exactly in their natural state, typified by our first site with its convenience store, giant dragon statue and the dulcet tones of Chinese opera rolling out across the lake. We assemble the boat, attach the motor and load the coring gear, sending the first team out onto the mirror-calm lake. During my turn on shore I explore the exposed lava field that separate the lakes, enjoying the early morning calm. Despite our early start, the first tourist bus arrives in time to see the team returning to shore with sediment cores and we gather quiet a crowd as we wrestle the cores back to the car.
We are sampling the lakes to look for a range of anthropogenic indicators by taking several sediment cores, conducting water quality tests and mapping the lakes bathymetry. The collected sediment is dark brown to black and smells strongly of decomposing organic material, likely due to the local agricultural activities. We are interested in understand the history of local anthropogenic pollutants such as pesticides, cadmium and lead and over the next few days we sample 3 of the 5 Wudalianchi Lakes. Despite the importance of the freshwater ecosystems to the local tourism and agricultural industry we suspect the lakes are changing rapidly due to local and regional anthropogenic impacts. On our final field day, we climb up Laoheishan (old black mountain), one of the younger volcanic cones. Hiking up through the young birch and conifer forests colonising the thin soils we quickly leave the tourists behind. At the top, we can see out over the exposed lava fields, well-tended corn and soy crops and the 5 lakes of Wudalianchi.
Sadly, it’s time for us to travel back to Nanjing and begin processing the sediment cores to extract their historical records. Arriving back in Nanjing we are greeted by a booming thunderstorm which can’t quite mask the heat. Our next field trip to the Great Hinggan Mountains in northeastern China can’t come soon enough!