143 / 2024-02-20 13:06:25

Concentrations of water carbon, nitrogen, and phosphorus and their response to hydrological connectivity in polders of Poyang Lake

biogenic element,Poyang Lake,Polder,Hydrological connectivity

Polder is an important component of Poyang Lake wetland. Reasonable concentration of key biogenic elements including carbon, nitrogen and phosphorus in polders is essential for the ecological function of the wetland. Taking the polders along the Le 'an River in Poyang Lake Basin as an example, through field monitoring and sampling, this study discovered the distribution pattern of concentration of dissolved carbon (DOC), nitrogen (DTN), and phosphorus (DTP) in major waterbodies of polders, as well as quantitatively revealed the effect of hydrological connectivity on element concentrations. All elements were distributed in the hierarchy of paddy field > pond > ditch. Concentration of biogenic elements was strongly correlated with hydrological connectivity, and the latter could explain up to 25.4% of the change of the former, indicating that with the improvement of connectivity, elements tended to shorten their residence time and accelerate turnover rate, causing decreased concentrations. The necessary measures to reduce the concentration of biogenic elements in polders are to establish the content and discharge standards of elements, and to carry out the practice of restoring hydrological connectivity in polders.